Fixed #34140 -- Reformatted code blocks in docs with blacken-docs.

4 files changed, 280 insertions, 184 deletions

diff --git a/docs/topics/forms/formsets.txt b/docs/topics/forms/formsets.txt
index 85c35dc2d0..a2e265a91f 100644
--- a/docs/topics/forms/formsets.txt
+++ b/docs/topics/forms/formsets.txt
@@ -16,6 +16,7 @@ form:
     >>> class ArticleForm(forms.Form):
     ...     title = forms.CharField()
     ...     pub_date = forms.DateField()
+    ...
 
 You might want to allow the user to create several articles at once. To create
 a formset out of an ``ArticleForm`` you would do:
@@ -34,6 +35,7 @@ in the formset and display them as you would with a regular form:
     >>> formset = ArticleFormSet()
     >>> for form in formset:
     ...     print(form)
+    ...
     <div><label for="id_form-0-title">Title:</label><input type="text" name="form-0-title" id="id_form-0-title"></div>
     <div><label for="id_form-0-pub_date">Pub date:</label><input type="text" name="form-0-pub_date" id="id_form-0-pub_date"></div>
 
@@ -71,13 +73,18 @@ example:
     >>> from django.forms import formset_factory
     >>> from myapp.forms import ArticleForm
     >>> ArticleFormSet = formset_factory(ArticleForm, extra=2)
-    >>> formset = ArticleFormSet(initial=[
-    ...     {'title': 'Django is now open source',
-    ...      'pub_date': datetime.date.today(),}
-    ... ])
+    >>> formset = ArticleFormSet(
+    ...     initial=[
+    ...         {
+    ...             "title": "Django is now open source",
+    ...             "pub_date": datetime.date.today(),
+    ...         }
+    ...     ]
+    ... )
 
     >>> for form in formset:
     ...     print(form)
+    ...
     <div><label for="id_form-0-title">Title:</label><input type="text" name="form-0-title" value="Django is now open source" id="id_form-0-title"></div>
     <div><label for="id_form-0-pub_date">Pub date:</label><input type="text" name="form-0-pub_date" value="2023-02-11" id="id_form-0-pub_date"></div>
     <div><label for="id_form-1-title">Title:</label><input type="text" name="form-1-title" id="id_form-1-title"></div>
@@ -114,6 +121,7 @@ gives you the ability to limit the number of forms the formset will display:
     >>> formset = ArticleFormSet()
     >>> for form in formset:
     ...     print(form)
+    ...
     <div><label for="id_form-0-title">Title:</label><input type="text" name="form-0-title" id="id_form-0-title"></div>
     <div><label for="id_form-0-pub_date">Pub date:</label><input type="text" name="form-0-pub_date" id="id_form-0-pub_date"></div>
 
@@ -153,8 +161,8 @@ protects against memory exhaustion attacks using forged ``POST`` requests:
     >>> from myapp.forms import ArticleForm
     >>> ArticleFormSet = formset_factory(ArticleForm, absolute_max=1500)
     >>> data = {
-    ...     'form-TOTAL_FORMS': '1501',
-    ...     'form-INITIAL_FORMS': '0',
+    ...     "form-TOTAL_FORMS": "1501",
+    ...     "form-INITIAL_FORMS": "0",
     ... }
     >>> formset = ArticleFormSet(data)
     >>> len(formset.forms)
@@ -182,8 +190,8 @@ all forms in the formset:
     >>> from myapp.forms import ArticleForm
     >>> ArticleFormSet = formset_factory(ArticleForm)
     >>> data = {
-    ...     'form-TOTAL_FORMS': '1',
-    ...     'form-INITIAL_FORMS': '0',
+    ...     "form-TOTAL_FORMS": "1",
+    ...     "form-INITIAL_FORMS": "0",
     ... }
     >>> formset = ArticleFormSet(data)
     >>> formset.is_valid()
@@ -196,12 +204,12 @@ provide an invalid article:
 .. code-block:: pycon
 
     >>> data = {
-    ...     'form-TOTAL_FORMS': '2',
-    ...     'form-INITIAL_FORMS': '0',
-    ...     'form-0-title': 'Test',
-    ...     'form-0-pub_date': '1904-06-16',
-    ...     'form-1-title': 'Test',
-    ...     'form-1-pub_date': '', # <-- this date is missing but required
+    ...     "form-TOTAL_FORMS": "2",
+    ...     "form-INITIAL_FORMS": "0",
+    ...     "form-0-title": "Test",
+    ...     "form-0-pub_date": "1904-06-16",
+    ...     "form-1-title": "Test",
+    ...     "form-1-pub_date": "",  # <-- this date is missing but required
     ... }
     >>> formset = ArticleFormSet(data)
     >>> formset.is_valid()
@@ -239,10 +247,10 @@ sent without any data):
 .. code-block:: pycon
 
     >>> data = {
-    ...     'form-TOTAL_FORMS': '1',
-    ...     'form-INITIAL_FORMS': '0',
-    ...     'form-0-title': '',
-    ...     'form-0-pub_date': '',
+    ...     "form-TOTAL_FORMS": "1",
+    ...     "form-INITIAL_FORMS": "0",
+    ...     "form-0-title": "",
+    ...     "form-0-pub_date": "",
     ... }
     >>> formset = ArticleFormSet(data)
     >>> formset.has_changed()
@@ -262,8 +270,8 @@ provide this management data, the formset will be invalid:
 .. code-block:: pycon
 
     >>> data = {
-    ...     'form-0-title': 'Test',
-    ...     'form-0-pub_date': '',
+    ...     "form-0-title": "Test",
+    ...     "form-0-pub_date": "",
     ... }
     >>> formset = ArticleFormSet(data)
     >>> formset.is_valid()
@@ -339,7 +347,9 @@ And here is a custom error message:
 
 .. code-block:: pycon
 
-    >>> formset = ArticleFormSet({}, error_messages={'missing_management_form': 'Sorry, something went wrong.'})
+    >>> formset = ArticleFormSet(
+    ...     {}, error_messages={"missing_management_form": "Sorry, something went wrong."}
+    ... )
     >>> formset.is_valid()
     False
     >>> formset.non_form_errors()
@@ -368,19 +378,20 @@ is where you define your own validation that works at the formset level:
     ...         for form in self.forms:
     ...             if self.can_delete and self._should_delete_form(form):
     ...                 continue
-    ...             title = form.cleaned_data.get('title')
+    ...             title = form.cleaned_data.get("title")
     ...             if title in titles:
     ...                 raise ValidationError("Articles in a set must have distinct titles.")
     ...             titles.append(title)
+    ...
 
     >>> ArticleFormSet = formset_factory(ArticleForm, formset=BaseArticleFormSet)
     >>> data = {
-    ...     'form-TOTAL_FORMS': '2',
-    ...     'form-INITIAL_FORMS': '0',
-    ...     'form-0-title': 'Test',
-    ...     'form-0-pub_date': '1904-06-16',
-    ...     'form-1-title': 'Test',
-    ...     'form-1-pub_date': '1912-06-23',
+    ...     "form-TOTAL_FORMS": "2",
+    ...     "form-INITIAL_FORMS": "0",
+    ...     "form-0-title": "Test",
+    ...     "form-0-pub_date": "1904-06-16",
+    ...     "form-1-title": "Test",
+    ...     "form-1-pub_date": "1912-06-23",
     ... }
     >>> formset = ArticleFormSet(data)
     >>> formset.is_valid()
@@ -512,12 +523,15 @@ Lets you create a formset with the ability to order:
     >>> from django.forms import formset_factory
     >>> from myapp.forms import ArticleForm
     >>> ArticleFormSet = formset_factory(ArticleForm, can_order=True)
-    >>> formset = ArticleFormSet(initial=[
-    ...     {'title': 'Article #1', 'pub_date': datetime.date(2008, 5, 10)},
-    ...     {'title': 'Article #2', 'pub_date': datetime.date(2008, 5, 11)},
-    ... ])
+    >>> formset = ArticleFormSet(
+    ...     initial=[
+    ...         {"title": "Article #1", "pub_date": datetime.date(2008, 5, 10)},
+    ...         {"title": "Article #2", "pub_date": datetime.date(2008, 5, 11)},
+    ...     ]
+    ... )
     >>> for form in formset:
     ...     print(form)
+    ...
     <div><label for="id_form-0-title">Title:</label><input type="text" name="form-0-title" value="Article #1" id="id_form-0-title"></div>
     <div><label for="id_form-0-pub_date">Pub date:</label><input type="text" name="form-0-pub_date" value="2008-05-10" id="id_form-0-pub_date"></div>
     <div><label for="id_form-0-ORDER">Order:</label><input type="number" name="form-0-ORDER" value="1" id="id_form-0-ORDER"></div>
@@ -536,27 +550,31 @@ happen when the user changes these values:
 .. code-block:: pycon
 
     >>> data = {
-    ...     'form-TOTAL_FORMS': '3',
-    ...     'form-INITIAL_FORMS': '2',
-    ...     'form-0-title': 'Article #1',
-    ...     'form-0-pub_date': '2008-05-10',
-    ...     'form-0-ORDER': '2',
-    ...     'form-1-title': 'Article #2',
-    ...     'form-1-pub_date': '2008-05-11',
-    ...     'form-1-ORDER': '1',
-    ...     'form-2-title': 'Article #3',
-    ...     'form-2-pub_date': '2008-05-01',
-    ...     'form-2-ORDER': '0',
+    ...     "form-TOTAL_FORMS": "3",
+    ...     "form-INITIAL_FORMS": "2",
+    ...     "form-0-title": "Article #1",
+    ...     "form-0-pub_date": "2008-05-10",
+    ...     "form-0-ORDER": "2",
+    ...     "form-1-title": "Article #2",
+    ...     "form-1-pub_date": "2008-05-11",
+    ...     "form-1-ORDER": "1",
+    ...     "form-2-title": "Article #3",
+    ...     "form-2-pub_date": "2008-05-01",
+    ...     "form-2-ORDER": "0",
     ... }
 
-    >>> formset = ArticleFormSet(data, initial=[
-    ...     {'title': 'Article #1', 'pub_date': datetime.date(2008, 5, 10)},
-    ...     {'title': 'Article #2', 'pub_date': datetime.date(2008, 5, 11)},
-    ... ])
+    >>> formset = ArticleFormSet(
+    ...     data,
+    ...     initial=[
+    ...         {"title": "Article #1", "pub_date": datetime.date(2008, 5, 10)},
+    ...         {"title": "Article #2", "pub_date": datetime.date(2008, 5, 11)},
+    ...     ],
+    ... )
     >>> formset.is_valid()
     True
     >>> for form in formset.ordered_forms:
     ...     print(form.cleaned_data)
+    ...
     {'pub_date': datetime.date(2008, 5, 1), 'ORDER': 0, 'title': 'Article #3'}
     {'pub_date': datetime.date(2008, 5, 11), 'ORDER': 1, 'title': 'Article #2'}
     {'pub_date': datetime.date(2008, 5, 10), 'ORDER': 2, 'title': 'Article #1'}
@@ -583,8 +601,11 @@ Set ``ordering_widget`` to specify the widget class to be used with
     >>> from myapp.forms import ArticleForm
     >>> class BaseArticleFormSet(BaseFormSet):
     ...     ordering_widget = HiddenInput
+    ...
 
-    >>> ArticleFormSet = formset_factory(ArticleForm, formset=BaseArticleFormSet, can_order=True)
+    >>> ArticleFormSet = formset_factory(
+    ...     ArticleForm, formset=BaseArticleFormSet, can_order=True
+    ... )
 
 ``get_ordering_widget``
 ^^^^^^^^^^^^^^^^^^^^^^^
@@ -600,9 +621,12 @@ use with ``can_order``:
     >>> from myapp.forms import ArticleForm
     >>> class BaseArticleFormSet(BaseFormSet):
     ...     def get_ordering_widget(self):
-    ...         return HiddenInput(attrs={'class': 'ordering'})
+    ...         return HiddenInput(attrs={"class": "ordering"})
+    ...
 
-    >>> ArticleFormSet = formset_factory(ArticleForm, formset=BaseArticleFormSet, can_order=True)
+    >>> ArticleFormSet = formset_factory(
+    ...     ArticleForm, formset=BaseArticleFormSet, can_order=True
+    ... )
 
 ``can_delete``
 --------------
@@ -618,12 +642,15 @@ Lets you create a formset with the ability to select forms for deletion:
     >>> from django.forms import formset_factory
     >>> from myapp.forms import ArticleForm
     >>> ArticleFormSet = formset_factory(ArticleForm, can_delete=True)
-    >>> formset = ArticleFormSet(initial=[
-    ...     {'title': 'Article #1', 'pub_date': datetime.date(2008, 5, 10)},
-    ...     {'title': 'Article #2', 'pub_date': datetime.date(2008, 5, 11)},
-    ... ])
+    >>> formset = ArticleFormSet(
+    ...     initial=[
+    ...         {"title": "Article #1", "pub_date": datetime.date(2008, 5, 10)},
+    ...         {"title": "Article #2", "pub_date": datetime.date(2008, 5, 11)},
+    ...     ]
+    ... )
     >>> for form in formset:
     ...     print(form)
+    ...
     <div><label for="id_form-0-title">Title:</label><input type="text" name="form-0-title" value="Article #1" id="id_form-0-title"></div>
     <div><label for="id_form-0-pub_date">Pub date:</label><input type="text" name="form-0-pub_date" value="2008-05-10" id="id_form-0-pub_date"></div>
     <div><label for="id_form-0-DELETE">Delete:</label><input type="checkbox" name="form-0-DELETE" id="id_form-0-DELETE"></div>
@@ -641,23 +668,26 @@ delete fields you can access them with ``deleted_forms``:
 .. code-block:: pycon
 
     >>> data = {
-    ...     'form-TOTAL_FORMS': '3',
-    ...     'form-INITIAL_FORMS': '2',
-    ...     'form-0-title': 'Article #1',
-    ...     'form-0-pub_date': '2008-05-10',
-    ...     'form-0-DELETE': 'on',
-    ...     'form-1-title': 'Article #2',
-    ...     'form-1-pub_date': '2008-05-11',
-    ...     'form-1-DELETE': '',
-    ...     'form-2-title': '',
-    ...     'form-2-pub_date': '',
-    ...     'form-2-DELETE': '',
+    ...     "form-TOTAL_FORMS": "3",
+    ...     "form-INITIAL_FORMS": "2",
+    ...     "form-0-title": "Article #1",
+    ...     "form-0-pub_date": "2008-05-10",
+    ...     "form-0-DELETE": "on",
+    ...     "form-1-title": "Article #2",
+    ...     "form-1-pub_date": "2008-05-11",
+    ...     "form-1-DELETE": "",
+    ...     "form-2-title": "",
+    ...     "form-2-pub_date": "",
+    ...     "form-2-DELETE": "",
     ... }
 
-    >>> formset = ArticleFormSet(data, initial=[
-    ...     {'title': 'Article #1', 'pub_date': datetime.date(2008, 5, 10)},
-    ...     {'title': 'Article #2', 'pub_date': datetime.date(2008, 5, 11)},
-    ... ])
+    >>> formset = ArticleFormSet(
+    ...     data,
+    ...     initial=[
+    ...         {"title": "Article #1", "pub_date": datetime.date(2008, 5, 10)},
+    ...         {"title": "Article #2", "pub_date": datetime.date(2008, 5, 11)},
+    ...     ],
+    ... )
     >>> [form.cleaned_data for form in formset.deleted_forms]
     [{'DELETE': True, 'pub_date': datetime.date(2008, 5, 10), 'title': 'Article #1'}]
 
@@ -676,6 +706,7 @@ them:
     >>> instances = formset.save(commit=False)
     >>> for obj in formset.deleted_objects:
     ...     obj.delete()
+    ...
 
 On the other hand, if you are using a plain ``FormSet``, it's up to you to
 handle ``formset.deleted_forms``, perhaps in your formset's ``save()`` method,
@@ -703,8 +734,11 @@ Set ``deletion_widget`` to specify the widget class to be used with
     >>> from myapp.forms import ArticleForm
     >>> class BaseArticleFormSet(BaseFormSet):
     ...     deletion_widget = HiddenInput
+    ...
 
-    >>> ArticleFormSet = formset_factory(ArticleForm, formset=BaseArticleFormSet, can_delete=True)
+    >>> ArticleFormSet = formset_factory(
+    ...     ArticleForm, formset=BaseArticleFormSet, can_delete=True
+    ... )
 
 ``get_deletion_widget``
 ^^^^^^^^^^^^^^^^^^^^^^^
@@ -720,9 +754,12 @@ use with ``can_delete``:
     >>> from myapp.forms import ArticleForm
     >>> class BaseArticleFormSet(BaseFormSet):
     ...     def get_deletion_widget(self):
-    ...         return HiddenInput(attrs={'class': 'deletion'})
+    ...         return HiddenInput(attrs={"class": "deletion"})
+    ...
 
-    >>> ArticleFormSet = formset_factory(ArticleForm, formset=BaseArticleFormSet, can_delete=True)
+    >>> ArticleFormSet = formset_factory(
+    ...     ArticleForm, formset=BaseArticleFormSet, can_delete=True
+    ... )
 
 ``can_delete_extra``
 --------------------
@@ -751,11 +788,13 @@ fields/attributes of the order and deletion fields:
     ...     def add_fields(self, form, index):
     ...         super().add_fields(form, index)
     ...         form.fields["my_field"] = forms.CharField()
+    ...
 
     >>> ArticleFormSet = formset_factory(ArticleForm, formset=BaseArticleFormSet)
     >>> formset = ArticleFormSet()
     >>> for form in formset:
     ...     print(form)
+    ...
     <div><label for="id_form-0-title">Title:</label><input type="text" name="form-0-title" id="id_form-0-title"></div>
     <div><label for="id_form-0-pub_date">Pub date:</label><input type="text" name="form-0-pub_date" id="id_form-0-pub_date"></div>
     <div><label for="id_form-0-my_field">My field:</label><input type="text" name="form-0-my_field" id="id_form-0-my_field"></div>
@@ -778,9 +817,10 @@ You can pass this parameter when instantiating the formset:
     ...     def __init__(self, *args, user, **kwargs):
     ...         self.user = user
     ...         super().__init__(*args, **kwargs)
+    ...
 
     >>> ArticleFormSet = formset_factory(MyArticleForm)
-    >>> formset = ArticleFormSet(form_kwargs={'user': request.user})
+    >>> formset = ArticleFormSet(form_kwargs={"user": request.user})
 
 The ``form_kwargs`` may also depend on the specific form instance. The formset
 base class provides a ``get_form_kwargs`` method. The method takes a single
@@ -795,8 +835,9 @@ argument - the index of the form in the formset. The index is ``None`` for the
     >>> class BaseArticleFormSet(BaseFormSet):
     ...     def get_form_kwargs(self, index):
     ...         kwargs = super().get_form_kwargs(index)
-    ...         kwargs['custom_kwarg'] = index
+    ...         kwargs["custom_kwarg"] = index
     ...         return kwargs
+    ...
 
     >>> ArticleFormSet = formset_factory(MyArticleForm, formset=BaseArticleFormSet)
     >>> formset = ArticleFormSet()
@@ -924,16 +965,17 @@ use the management form inside the template. Let's look at a sample view::
     from django.shortcuts import render
     from myapp.forms import ArticleForm
 
+
     def manage_articles(request):
         ArticleFormSet = formset_factory(ArticleForm)
-        if request.method == 'POST':
+        if request.method == "POST":
             formset = ArticleFormSet(request.POST, request.FILES)
             if formset.is_valid():
                 # do something with the formset.cleaned_data
                 pass
         else:
             formset = ArticleFormSet()
-        return render(request, 'manage_articles.html', {'formset': formset})
+        return render(request, "manage_articles.html", {"formset": formset})
 
 The ``manage_articles.html`` template might look like this:
 
@@ -1009,22 +1051,27 @@ a look at how this might be accomplished::
     from django.shortcuts import render
     from myapp.forms import ArticleForm, BookForm
 
+
     def manage_articles(request):
         ArticleFormSet = formset_factory(ArticleForm)
         BookFormSet = formset_factory(BookForm)
-        if request.method == 'POST':
-            article_formset = ArticleFormSet(request.POST, request.FILES, prefix='articles')
-            book_formset = BookFormSet(request.POST, request.FILES, prefix='books')
+        if request.method == "POST":
+            article_formset = ArticleFormSet(request.POST, request.FILES, prefix="articles")
+            book_formset = BookFormSet(request.POST, request.FILES, prefix="books")
             if article_formset.is_valid() and book_formset.is_valid():
                 # do something with the cleaned_data on the formsets.
                 pass
         else:
-            article_formset = ArticleFormSet(prefix='articles')
-            book_formset = BookFormSet(prefix='books')
-        return render(request, 'manage_articles.html', {
-            'article_formset': article_formset,
-            'book_formset': book_formset,
-        })
+            article_formset = ArticleFormSet(prefix="articles")
+            book_formset = BookFormSet(prefix="books")
+        return render(
+            request,
+            "manage_articles.html",
+            {
+                "article_formset": article_formset,
+                "book_formset": book_formset,
+            },
+        )
 
 You would then render the formsets as normal. It is important to point out
 that you need to pass ``prefix`` on both the POST and non-POST cases so that
diff --git a/docs/topics/forms/index.txt b/docs/topics/forms/index.txt
index 3d409f5f06..fec2b03251 100644
--- a/docs/topics/forms/index.txt
+++ b/docs/topics/forms/index.txt
@@ -231,8 +231,9 @@ it in Django is this:
 
     from django import forms
 
+
     class NameForm(forms.Form):
-        your_name = forms.CharField(label='Your name', max_length=100)
+        your_name = forms.CharField(label="Your name", max_length=100)
 
 This defines a :class:`Form` class with a single field (``your_name``). We've
 applied a human-friendly label to the field, which will appear in the
@@ -284,9 +285,10 @@ want it to be published:
 
     from .forms import NameForm
 
+
     def get_name(request):
         # if this is a POST request we need to process the form data
-        if request.method == 'POST':
+        if request.method == "POST":
             # create a form instance and populate it with data from the request:
             form = NameForm(request.POST)
             # check whether it's valid:
@@ -294,13 +296,13 @@ want it to be published:
                 # process the data in form.cleaned_data as required
                 # ...
                 # redirect to a new URL:
-                return HttpResponseRedirect('/thanks/')
+                return HttpResponseRedirect("/thanks/")
 
         # if a GET (or any other method) we'll create a blank form
         else:
             form = NameForm()
 
-        return render(request, 'name.html', {'form': form})
+        return render(request, "name.html", {"form": form})
 
 If we arrive at this view with a ``GET`` request, it will create an empty form
 instance and place it in the template context to be rendered. This is what we
@@ -408,6 +410,7 @@ to implement "contact me" functionality on a personal website:
 
     from django import forms
 
+
     class ContactForm(forms.Form):
         subject = forms.CharField(max_length=100)
         message = forms.CharField(widget=forms.Textarea)
@@ -458,17 +461,17 @@ Here's how the form data could be processed in the view that handles this form:
     from django.core.mail import send_mail
 
     if form.is_valid():
-        subject = form.cleaned_data['subject']
-        message = form.cleaned_data['message']
-        sender = form.cleaned_data['sender']
-        cc_myself = form.cleaned_data['cc_myself']
+        subject = form.cleaned_data["subject"]
+        message = form.cleaned_data["message"]
+        sender = form.cleaned_data["sender"]
+        cc_myself = form.cleaned_data["cc_myself"]
 
-        recipients = ['info@example.com']
+        recipients = ["info@example.com"]
         if cc_myself:
             recipients.append(sender)
 
         send_mail(subject, message, sender, recipients)
-        return HttpResponseRedirect('/thanks/')
+        return HttpResponseRedirect("/thanks/")
 
 .. tip::
 
@@ -532,9 +535,11 @@ Then you can configure the :setting:`FORM_RENDERER` setting:
 
     from django.forms.renderers import TemplatesSetting
 
+
     class CustomFormRenderer(TemplatesSetting):
         form_template_name = "form_snippet.html"
 
+
     FORM_RENDERER = "project.settings.CustomFormRenderer"
 
 … or for a single form::
@@ -549,8 +554,8 @@ the :meth:`.Form.render`. Here's an example of this being used in a view::
     def index(request):
         form = MyForm()
         rendered_form = form.render("form_snippet.html")
-        context = {'form': rendered_form}
-        return render(request, 'index.html', context)
+        context = {"form": rendered_form}
+        return render(request, "index.html", context)
 
 See :ref:`ref-forms-api-outputting-html` for more details.
 
diff --git a/docs/topics/forms/media.txt b/docs/topics/forms/media.txt
index ab37a19182..5fdd37437e 100644
--- a/docs/topics/forms/media.txt
+++ b/docs/topics/forms/media.txt
@@ -53,12 +53,13 @@ Here's an example::
 
     from django import forms
 
+
     class CalendarWidget(forms.TextInput):
         class Media:
             css = {
-                'all': ['pretty.css'],
+                "all": ["pretty.css"],
             }
-            js = ['animations.js', 'actions.js']
+            js = ["animations.js", "actions.js"]
 
 This code defines a ``CalendarWidget``, which will be based on ``TextInput``.
 Every time the CalendarWidget is used on a form, that form will be directed
@@ -98,8 +99,8 @@ provide two CSS options -- one for the screen, and one for print::
 
     class Media:
         css = {
-            'screen': ['pretty.css'],
-            'print': ['newspaper.css'],
+            "screen": ["pretty.css"],
+            "print": ["newspaper.css"],
         }
 
 If a group of CSS files are appropriate for multiple output media types,
@@ -109,9 +110,9 @@ requirements::
 
     class Media:
         css = {
-            'screen': ['pretty.css'],
-            'tv,projector': ['lo_res.css'],
-            'print': ['newspaper.css'],
+            "screen": ["pretty.css"],
+            "tv,projector": ["lo_res.css"],
+            "print": ["newspaper.css"],
         }
 
 If this last CSS definition were to be rendered, it would become the following HTML:
@@ -145,9 +146,10 @@ example above:
     >>> class FancyCalendarWidget(CalendarWidget):
     ...     class Media:
     ...         css = {
-    ...             'all': ['fancy.css'],
+    ...             "all": ["fancy.css"],
     ...         }
-    ...         js = ['whizbang.js']
+    ...         js = ["whizbang.js"]
+    ...
 
     >>> w = FancyCalendarWidget()
     >>> print(w.media)
@@ -167,9 +169,10 @@ an ``extend=False`` declaration to the ``Media`` declaration:
     ...     class Media:
     ...         extend = False
     ...         css = {
-    ...             'all': ['fancy.css'],
+    ...             "all": ["fancy.css"],
     ...         }
-    ...         js = ['whizbang.js']
+    ...         js = ["whizbang.js"]
+    ...
 
     >>> w = FancyCalendarWidget()
     >>> print(w.media)
@@ -198,8 +201,9 @@ be defined in a dynamic fashion::
     class CalendarWidget(forms.TextInput):
         @property
         def media(self):
-            return forms.Media(css={'all': ['pretty.css']},
-                               js=['animations.js', 'actions.js'])
+            return forms.Media(
+                css={"all": ["pretty.css"]}, js=["animations.js", "actions.js"]
+            )
 
 See the section on `Media objects`_ for more details on how to construct
 return values for dynamic ``media`` properties.
@@ -235,9 +239,10 @@ was ``None``:
     >>> class CalendarWidget(forms.TextInput):
     ...     class Media:
     ...         css = {
-    ...             'all': ['/css/pretty.css'],
+    ...             "all": ["/css/pretty.css"],
     ...         }
-    ...         js = ['animations.js', 'http://othersite.com/actions.js']
+    ...         js = ["animations.js", "http://othersite.com/actions.js"]
+    ...
 
     >>> w = CalendarWidget()
     >>> print(w.media)
@@ -283,10 +288,12 @@ outputting the complete HTML ``<script>`` or ``<link>`` tag content:
     ... class JSPath:
     ...     def __str__(self):
     ...         return '<script src="https://example.org/asset.js" rel="stylesheet">'
+    ...
 
     >>> class SomeWidget(forms.TextInput):
     ...     class Media:
     ...         js = [JSPath()]
+    ...
 
 ``Media`` objects
 =================
@@ -313,7 +320,7 @@ operator to filter out a medium of interest. For example:
     <script src="http://static.example.com/animations.js"></script>
     <script src="http://static.example.com/actions.js"></script>
 
-    >>> print(w.media['css'])
+    >>> print(w.media["css"])
     <link href="http://static.example.com/pretty.css" media="all" rel="stylesheet">
 
 When you use the subscript operator, the value that is returned is a
@@ -332,13 +339,15 @@ specified by both:
     >>> class CalendarWidget(forms.TextInput):
     ...     class Media:
     ...         css = {
-    ...             'all': ['pretty.css'],
+    ...             "all": ["pretty.css"],
     ...         }
-    ...         js = ['animations.js', 'actions.js']
+    ...         js = ["animations.js", "actions.js"]
+    ...
 
     >>> class OtherWidget(forms.TextInput):
     ...     class Media:
-    ...         js = ['whizbang.js']
+    ...         js = ["whizbang.js"]
+    ...
 
     >>> w1 = CalendarWidget()
     >>> w2 = OtherWidget()
@@ -365,10 +374,12 @@ For example:
     >>> from django import forms
     >>> class CalendarWidget(forms.TextInput):
     ...     class Media:
-    ...         js = ['jQuery.js', 'calendar.js', 'noConflict.js']
+    ...         js = ["jQuery.js", "calendar.js", "noConflict.js"]
+    ...
     >>> class TimeWidget(forms.TextInput):
     ...     class Media:
-    ...         js = ['jQuery.js', 'time.js', 'noConflict.js']
+    ...         js = ["jQuery.js", "time.js", "noConflict.js"]
+    ...
     >>> w1 = CalendarWidget()
     >>> w2 = TimeWidget()
     >>> print(w1.media + w2.media)
@@ -400,6 +411,7 @@ are part of the form:
     >>> class ContactForm(forms.Form):
     ...     date = DateField(widget=CalendarWidget)
     ...     name = CharField(max_length=40, widget=OtherWidget)
+    ...
 
     >>> f = ContactForm()
     >>> f.media
@@ -416,11 +428,11 @@ CSS for form layout -- add a ``Media`` declaration to the form:
     >>> class ContactForm(forms.Form):
     ...     date = DateField(widget=CalendarWidget)
     ...     name = CharField(max_length=40, widget=OtherWidget)
-    ...
     ...     class Media:
     ...         css = {
-    ...             'all': ['layout.css'],
+    ...             "all": ["layout.css"],
     ...         }
+    ...
 
     >>> f = ContactForm()
     >>> f.media
diff --git a/docs/topics/forms/modelforms.txt b/docs/topics/forms/modelforms.txt
index 50fb12ef6e..7f3c042f30 100644
--- a/docs/topics/forms/modelforms.txt
+++ b/docs/topics/forms/modelforms.txt
@@ -28,7 +28,8 @@ For example:
     >>> class ArticleForm(ModelForm):
     ...     class Meta:
     ...         model = Article
-    ...         fields = ['pub_date', 'headline', 'content', 'reporter']
+    ...         fields = ["pub_date", "headline", "content", "reporter"]
+    ...
 
     # Creating a form to add an article.
     >>> form = ArticleForm()
@@ -173,11 +174,12 @@ Consider this set of models::
     from django.forms import ModelForm
 
     TITLE_CHOICES = [
-        ('MR', 'Mr.'),
-        ('MRS', 'Mrs.'),
-        ('MS', 'Ms.'),
+        ("MR", "Mr."),
+        ("MRS", "Mrs."),
+        ("MS", "Ms."),
     ]
 
+
     class Author(models.Model):
         name = models.CharField(max_length=100)
         title = models.CharField(max_length=3, choices=TITLE_CHOICES)
@@ -186,19 +188,22 @@ Consider this set of models::
         def __str__(self):
             return self.name
 
+
     class Book(models.Model):
         name = models.CharField(max_length=100)
         authors = models.ManyToManyField(Author)
 
+
     class AuthorForm(ModelForm):
         class Meta:
             model = Author
-            fields = ['name', 'title', 'birth_date']
+            fields = ["name", "title", "birth_date"]
+
 
     class BookForm(ModelForm):
         class Meta:
             model = Book
-            fields = ['name', 'authors']
+            fields = ["name", "authors"]
 
 
 With these models, the ``ModelForm`` subclasses above would be roughly
@@ -207,6 +212,7 @@ we'll discuss in a moment.)::
 
     from django import forms
 
+
     class AuthorForm(forms.Form):
         name = forms.CharField(max_length=100)
         title = forms.CharField(
@@ -215,6 +221,7 @@ we'll discuss in a moment.)::
         )
         birth_date = forms.DateField(required=False)
 
+
     class BookForm(forms.Form):
         name = forms.CharField(max_length=100)
         authors = forms.ModelMultipleChoiceField(queryset=Author.objects.all())
@@ -305,11 +312,12 @@ to the ``error_messages`` dictionary of the ``ModelForm``’s inner ``Meta`` cla
     from django.core.exceptions import NON_FIELD_ERRORS
     from django.forms import ModelForm
 
+
     class ArticleForm(ModelForm):
         class Meta:
             error_messages = {
                 NON_FIELD_ERRORS: {
-                    'unique_together': "%(model_name)s's %(field_labels)s are not unique.",
+                    "unique_together": "%(model_name)s's %(field_labels)s are not unique.",
                 }
             }
 
@@ -388,7 +396,7 @@ you've manually saved the instance produced by the form, you can invoke
     >>> new_author = f.save(commit=False)
 
     # Modify the author in some way.
-    >>> new_author.some_field = 'some_value'
+    >>> new_author.some_field = "some_value"
 
     # Save the new instance.
     >>> new_author.save()
@@ -440,10 +448,11 @@ these security concerns do not apply to you:
 
        from django.forms import ModelForm
 
+
        class AuthorForm(ModelForm):
            class Meta:
                model = Author
-               fields = '__all__'
+               fields = "__all__"
 
 2. Set the ``exclude`` attribute of the ``ModelForm``’s inner ``Meta`` class to
    a list of fields to be excluded from the form.
@@ -453,7 +462,7 @@ these security concerns do not apply to you:
        class PartialAuthorForm(ModelForm):
            class Meta:
                model = Author
-               exclude = ['title']
+               exclude = ["title"]
 
    Since the ``Author`` model has the 3 fields ``name``, ``title`` and
    ``birth_date``, this will result in the fields ``name`` and ``birth_date``
@@ -481,7 +490,7 @@ include that field.
     avoid this failure, you must instantiate your model with initial
     values for the missing, but required fields::
 
-        author = Author(title='Mr')
+        author = Author(title="Mr")
         form = PartialAuthorForm(request.POST, instance=author)
         form.save()
 
@@ -490,7 +499,7 @@ include that field.
 
         form = PartialAuthorForm(request.POST)
         author = form.save(commit=False)
-        author.title = 'Mr'
+        author.title = "Mr"
         author.save()
 
     See the `section on saving forms`_ for more details on using
@@ -519,12 +528,13 @@ For example, if you want the ``CharField`` for the ``name`` attribute of
     from django.forms import ModelForm, Textarea
     from myapp.models import Author
 
+
     class AuthorForm(ModelForm):
         class Meta:
             model = Author
-            fields = ['name', 'title', 'birth_date']
+            fields = ["name", "title", "birth_date"]
             widgets = {
-                'name': Textarea(attrs={'cols': 80, 'rows': 20}),
+                "name": Textarea(attrs={"cols": 80, "rows": 20}),
             }
 
 The ``widgets`` dictionary accepts either widget instances (e.g.,
@@ -540,19 +550,20 @@ the ``name`` field::
 
     from django.utils.translation import gettext_lazy as _
 
+
     class AuthorForm(ModelForm):
         class Meta:
             model = Author
-            fields = ['name', 'title', 'birth_date']
+            fields = ["name", "title", "birth_date"]
             labels = {
-                'name': _('Writer'),
+                "name": _("Writer"),
             }
             help_texts = {
-                'name': _('Some useful help text.'),
+                "name": _("Some useful help text."),
             }
             error_messages = {
-                'name': {
-                    'max_length': _("This writer's name is too long."),
+                "name": {
+                    "max_length": _("This writer's name is too long."),
                 },
             }
 
@@ -565,12 +576,13 @@ field, you could do the following::
     from django.forms import ModelForm
     from myapp.models import Article
 
+
     class ArticleForm(ModelForm):
         class Meta:
             model = Article
-            fields = ['pub_date', 'headline', 'content', 'reporter', 'slug']
+            fields = ["pub_date", "headline", "content", "reporter", "slug"]
             field_classes = {
-                'slug': MySlugFormField,
+                "slug": MySlugFormField,
             }
 
 or::
@@ -578,11 +590,13 @@ or::
     from django.forms import ModelForm
     from myapp.models import Article
 
+
     def formfield_for_dbfield(db_field, **kwargs):
         if db_field.name == "slug":
             return MySlugFormField()
         return db_field.formfield(**kwargs)
 
+
     class ArticleForm(ModelForm):
         class Meta:
             model = Article
@@ -599,12 +613,13 @@ the field declaratively and setting its ``validators`` parameter::
     from django.forms import CharField, ModelForm
     from myapp.models import Article
 
+
     class ArticleForm(ModelForm):
         slug = CharField(validators=[validate_slug])
 
         class Meta:
             model = Article
-            fields = ['pub_date', 'headline', 'content', 'reporter', 'slug']
+            fields = ["pub_date", "headline", "content", "reporter", "slug"]
 
 .. note::
 
@@ -635,7 +650,7 @@ the field declaratively and setting its ``validators`` parameter::
                 max_length=200,
                 null=True,
                 blank=True,
-                help_text='Use puns liberally',
+                help_text="Use puns liberally",
             )
             content = models.TextField()
 
@@ -647,12 +662,12 @@ the field declaratively and setting its ``validators`` parameter::
             headline = MyFormField(
                 max_length=200,
                 required=False,
-                help_text='Use puns liberally',
+                help_text="Use puns liberally",
             )
 
             class Meta:
                 model = Article
-                fields = ['headline', 'content']
+                fields = ["headline", "content"]
 
     You must ensure that the type of the form field can be used to set the
     contents of the corresponding model field. When they are not compatible,
@@ -695,6 +710,7 @@ using the previous ``ArticleForm`` class:
     >>> class EnhancedArticleForm(ArticleForm):
     ...     def clean_pub_date(self):
     ...         ...
+    ...
 
 This creates a form that behaves identically to ``ArticleForm``, except there's
 some extra validation and cleaning for the ``pub_date`` field.
@@ -706,7 +722,8 @@ the ``Meta.fields`` or ``Meta.exclude`` lists:
 
     >>> class RestrictedArticleForm(EnhancedArticleForm):
     ...     class Meta(ArticleForm.Meta):
-    ...         exclude = ['body']
+    ...         exclude = ["body"]
+    ...
 
 This adds the extra method from the ``EnhancedArticleForm`` and modifies
 the original ``ArticleForm.Meta`` to remove one field.
@@ -744,8 +761,8 @@ and values from an attached model instance. For example:
     >>> article = Article.objects.get(pk=1)
     >>> article.headline
     'My headline'
-    >>> form = ArticleForm(initial={'headline': 'Initial headline'}, instance=article)
-    >>> form['headline'].value()
+    >>> form = ArticleForm(initial={"headline": "Initial headline"}, instance=article)
+    >>> form["headline"].value()
     'Initial headline'
 
 .. _modelforms-factory:
@@ -770,8 +787,7 @@ specifying the widgets to be used for a given field:
 .. code-block:: pycon
 
     >>> from django.forms import Textarea
-    >>> Form = modelform_factory(Book, form=BookForm,
-    ...                          widgets={"title": Textarea()})
+    >>> Form = modelform_factory(Book, form=BookForm, widgets={"title": Textarea()})
 
 The fields to include can be specified using the ``fields`` and ``exclude``
 keyword arguments, or the corresponding attributes on the ``ModelForm`` inner
@@ -799,7 +815,7 @@ convenient. Let's reuse the ``Author`` model from above:
 
     >>> from django.forms import modelformset_factory
     >>> from myapp.models import Author
-    >>> AuthorFormSet = modelformset_factory(Author, fields=['name', 'title'])
+    >>> AuthorFormSet = modelformset_factory(Author, fields=["name", "title"])
 
 Using ``fields`` restricts the formset to use only the given fields.
 Alternatively, you can take an "opt-out" approach, specifying which fields to
@@ -807,7 +823,7 @@ exclude:
 
 .. code-block:: pycon
 
-    >>> AuthorFormSet = modelformset_factory(Author, exclude=['birth_date'])
+    >>> AuthorFormSet = modelformset_factory(Author, exclude=["birth_date"])
 
 This will create a formset that is capable of working with the data associated
 with the ``Author`` model. It works just like a regular formset:
@@ -848,7 +864,7 @@ queryset that includes all objects in the model (e.g.,
 
 .. code-block:: pycon
 
-    >>> formset = AuthorFormSet(queryset=Author.objects.filter(name__startswith='O'))
+    >>> formset = AuthorFormSet(queryset=Author.objects.filter(name__startswith="O"))
 
 Alternatively, you can create a subclass that sets ``self.queryset`` in
 ``__init__``::
@@ -856,17 +872,19 @@ Alternatively, you can create a subclass that sets ``self.queryset`` in
     from django.forms import BaseModelFormSet
     from myapp.models import Author
 
+
     class BaseAuthorFormSet(BaseModelFormSet):
         def __init__(self, *args, **kwargs):
             super().__init__(*args, **kwargs)
-            self.queryset = Author.objects.filter(name__startswith='O')
+            self.queryset = Author.objects.filter(name__startswith="O")
 
 Then, pass your ``BaseAuthorFormSet`` class to the factory function:
 
 .. code-block:: pycon
 
     >>> AuthorFormSet = modelformset_factory(
-    ...     Author, fields=['name', 'title'], formset=BaseAuthorFormSet)
+    ...     Author, fields=["name", "title"], formset=BaseAuthorFormSet
+    ... )
 
 If you want to return a formset that doesn't include *any* preexisting
 instances of the model, you can specify an empty QuerySet:
@@ -886,7 +904,7 @@ you can create a custom model form that has custom validation::
     class AuthorForm(forms.ModelForm):
         class Meta:
             model = Author
-            fields = ['name', 'title']
+            fields = ["name", "title"]
 
         def clean_name(self):
             # custom validation for the name field
@@ -911,8 +929,10 @@ class of a ``ModelForm`` works:
 .. code-block:: pycon
 
     >>> AuthorFormSet = modelformset_factory(
-    ...     Author, fields=['name', 'title'],
-    ...     widgets={'name': Textarea(attrs={'cols': 80, 'rows': 20})})
+    ...     Author,
+    ...     fields=["name", "title"],
+    ...     widgets={"name": Textarea(attrs={"cols": 80, "rows": 20})},
+    ... )
 
 Enabling localization for fields with ``localized_fields``
 ----------------------------------------------------------
@@ -975,6 +995,7 @@ Pass ``commit=False`` to return the unsaved model instances:
     >>> for instance in instances:
     ...     # do something with instance
     ...     instance.save()
+    ...
 
 This gives you the ability to attach data to the instances before saving them
 to the database. If your formset contains a ``ManyToManyField``, you'll also
@@ -1001,11 +1022,11 @@ extra forms displayed.
 
 .. code-block:: pycon
 
-    >>> Author.objects.order_by('name')
+    >>> Author.objects.order_by("name")
     <QuerySet [<Author: Charles Baudelaire>, <Author: Paul Verlaine>, <Author: Walt Whitman>]>
 
-    >>> AuthorFormSet = modelformset_factory(Author, fields=['name'], max_num=1)
-    >>> formset = AuthorFormSet(queryset=Author.objects.order_by('name'))
+    >>> AuthorFormSet = modelformset_factory(Author, fields=["name"], max_num=1)
+    >>> formset = AuthorFormSet(queryset=Author.objects.order_by("name"))
     >>> [x.name for x in formset.get_queryset()]
     ['Charles Baudelaire', 'Paul Verlaine', 'Walt Whitman']
 
@@ -1020,10 +1041,11 @@ so long as the total number of forms does not exceed ``max_num``:
 
 .. code-block:: pycon
 
-    >>> AuthorFormSet = modelformset_factory(Author, fields=['name'], max_num=4, extra=2)
-    >>> formset = AuthorFormSet(queryset=Author.objects.order_by('name'))
+    >>> AuthorFormSet = modelformset_factory(Author, fields=["name"], max_num=4, extra=2)
+    >>> formset = AuthorFormSet(queryset=Author.objects.order_by("name"))
     >>> for form in formset:
     ...     print(form)
+    ...
     <div><label for="id_form-0-name">Name:</label><input id="id_form-0-name" type="text" name="form-0-name" value="Charles Baudelaire" maxlength="100"><input type="hidden" name="form-0-id" value="1" id="id_form-0-id"></div>
     <div><label for="id_form-1-name">Name:</label><input id="id_form-1-name" type="text" name="form-1-name" value="Paul Verlaine" maxlength="100"><input type="hidden" name="form-1-id" value="3" id="id_form-1-id"></div>
     <div><label for="id_form-2-name">Name:</label><input id="id_form-2-name" type="text" name="form-2-name" value="Walt Whitman" maxlength="100"><input type="hidden" name="form-2-id" value="2" id="id_form-2-id"></div>
@@ -1044,7 +1066,7 @@ objects:
 
     >>> AuthorFormSet = modelformset_factory(
     ...     Author,
-    ...     fields=['name', 'title'],
+    ...     fields=["name", "title"],
     ...     edit_only=True,
     ... )
 
@@ -1061,16 +1083,17 @@ formset to edit ``Author`` model instances::
     from django.shortcuts import render
     from myapp.models import Author
 
+
     def manage_authors(request):
-        AuthorFormSet = modelformset_factory(Author, fields=['name', 'title'])
-        if request.method == 'POST':
+        AuthorFormSet = modelformset_factory(Author, fields=["name", "title"])
+        if request.method == "POST":
             formset = AuthorFormSet(request.POST, request.FILES)
             if formset.is_valid():
                 formset.save()
                 # do something.
         else:
             formset = AuthorFormSet()
-        return render(request, 'manage_authors.html', {'formset': formset})
+        return render(request, "manage_authors.html", {"formset": formset})
 
 As you can see, the view logic of a model formset isn't drastically different
 than that of a "normal" formset. The only difference is that we call
@@ -1091,6 +1114,7 @@ class's ``clean`` method::
 
     from django.forms import BaseModelFormSet
 
+
     class MyModelFormSet(BaseModelFormSet):
         def clean(self):
             super().clean()
@@ -1107,13 +1131,14 @@ to modify a value in ``ModelFormSet.clean()`` you must modify
 
     from django.forms import BaseModelFormSet
 
+
     class MyModelFormSet(BaseModelFormSet):
         def clean(self):
             super().clean()
 
             for form in self.forms:
-                name = form.cleaned_data['name'].upper()
-                form.cleaned_data['name'] = name
+                name = form.cleaned_data["name"].upper()
+                form.cleaned_data["name"] = name
                 # update the instance value.
                 form.instance.name = name
 
@@ -1127,12 +1152,14 @@ formset::
     from django.shortcuts import render
     from myapp.models import Author
 
+
     def manage_authors(request):
-        AuthorFormSet = modelformset_factory(Author, fields=['name', 'title'])
-        queryset = Author.objects.filter(name__startswith='O')
+        AuthorFormSet = modelformset_factory(Author, fields=["name", "title"])
+        queryset = Author.objects.filter(name__startswith="O")
         if request.method == "POST":
             formset = AuthorFormSet(
-                request.POST, request.FILES,
+                request.POST,
+                request.FILES,
                 queryset=queryset,
             )
             if formset.is_valid():
@@ -1140,7 +1167,7 @@ formset::
                 # Do something.
         else:
             formset = AuthorFormSet(queryset=queryset)
-        return render(request, 'manage_authors.html', {'formset': formset})
+        return render(request, "manage_authors.html", {"formset": formset})
 
 Note that we pass the ``queryset`` argument in both the ``POST`` and ``GET``
 cases in this example.
@@ -1222,9 +1249,11 @@ you have these two models::
 
     from django.db import models
 
+
     class Author(models.Model):
         name = models.CharField(max_length=100)
 
+
     class Book(models.Model):
         author = models.ForeignKey(Author, on_delete=models.CASCADE)
         title = models.CharField(max_length=100)
@@ -1235,8 +1264,8 @@ a particular author, you could do this:
 .. code-block:: pycon
 
     >>> from django.forms import inlineformset_factory
-    >>> BookFormSet = inlineformset_factory(Author, Book, fields=['title'])
-    >>> author = Author.objects.get(name='Mike Royko')
+    >>> BookFormSet = inlineformset_factory(Author, Book, fields=["title"])
+    >>> author = Author.objects.get(name="Mike Royko")
     >>> formset = BookFormSet(instance=author)
 
 ``BookFormSet``'s :ref:`prefix <formset-prefix>` is ``'book_set'``
@@ -1264,6 +1293,7 @@ For example, if you want to override ``clean()``::
 
     from django.forms import BaseInlineFormSet
 
+
     class CustomInlineFormSet(BaseInlineFormSet):
         def clean(self):
             super().clean()
@@ -1280,9 +1310,10 @@ Then when you create your inline formset, pass in the optional argument
 .. code-block:: pycon
 
     >>> from django.forms import inlineformset_factory
-    >>> BookFormSet = inlineformset_factory(Author, Book, fields=['title'],
-    ...     formset=CustomInlineFormSet)
-    >>> author = Author.objects.get(name='Mike Royko')
+    >>> BookFormSet = inlineformset_factory(
+    ...     Author, Book, fields=["title"], formset=CustomInlineFormSet
+    ... )
+    >>> author = Author.objects.get(name="Mike Royko")
     >>> formset = BookFormSet(instance=author)
 
 More than one foreign key to the same model
@@ -1296,12 +1327,12 @@ the following model::
         from_friend = models.ForeignKey(
             Friend,
             on_delete=models.CASCADE,
-            related_name='from_friends',
+            related_name="from_friends",
         )
         to_friend = models.ForeignKey(
             Friend,
             on_delete=models.CASCADE,
-            related_name='friends',
+            related_name="friends",
         )
         length_in_months = models.IntegerField()
 
@@ -1310,8 +1341,9 @@ To resolve this, you can use ``fk_name`` to
 
 .. code-block:: pycon
 
-    >>> FriendshipFormSet = inlineformset_factory(Friend, Friendship, fk_name='from_friend',
-    ...     fields=['to_friend', 'length_in_months'])
+    >>> FriendshipFormSet = inlineformset_factory(
+    ...     Friend, Friendship, fk_name="from_friend", fields=["to_friend", "length_in_months"]
+    ... )
 
 Using an inline formset in a view
 ---------------------------------
@@ -1321,7 +1353,7 @@ of a model. Here's how you can do that::
 
     def manage_books(request, author_id):
         author = Author.objects.get(pk=author_id)
-        BookInlineFormSet = inlineformset_factory(Author, Book, fields=['title'])
+        BookInlineFormSet = inlineformset_factory(Author, Book, fields=["title"])
         if request.method == "POST":
             formset = BookInlineFormSet(request.POST, request.FILES, instance=author)
             if formset.is_valid():
@@ -1330,7 +1362,7 @@ of a model. Here's how you can do that::
                 return HttpResponseRedirect(author.get_absolute_url())
         else:
             formset = BookInlineFormSet(instance=author)
-        return render(request, 'manage_books.html', {'formset': formset})
+        return render(request, "manage_books.html", {"formset": formset})
 
 Notice how we pass ``instance`` in both the ``POST`` and ``GET`` cases.