[1.8.x] Sorted imports with isort; refs #23860.

Backport of 0ed7d155635da9f79d4dd67e4889087d3673c6da from master

49 files changed, 148 insertions, 149 deletions

diff --git a/django/db/backends/base/base.py b/django/db/backends/base/base.py
index 5c0e8755ea..ad6b4f3df1 100644
--- a/django/db/backends/base/base.py
+++ b/django/db/backends/base/base.py
@@ -1,18 +1,17 @@
-from collections import deque
-from contextlib import contextmanager
 import time
 import warnings
+from collections import deque
+from contextlib import contextmanager
 
 from django.conf import settings
 from django.db import DEFAULT_DB_ALIAS
-from django.db.backends.signals import connection_created
 from django.db.backends import utils
+from django.db.backends.signals import connection_created
 from django.db.transaction import TransactionManagementError
 from django.db.utils import DatabaseError, DatabaseErrorWrapper
 from django.utils.functional import cached_property
 from django.utils.six.moves import _thread as thread
 
-
 NO_DB_ALIAS = '__no_db__'
 
 
diff --git a/django/db/backends/base/creation.py b/django/db/backends/base/creation.py
index 35cabba0cf..a077950627 100644
--- a/django/db/backends/base/creation.py
+++ b/django/db/backends/base/creation.py
@@ -13,7 +13,6 @@ from django.utils.encoding import force_bytes
 from django.utils.six import StringIO
 from django.utils.six.moves import input
 
-
 # The prefix to put on the default database name when creating
 # the test database.
 TEST_DATABASE_PREFIX = 'test_'
diff --git a/django/db/backends/base/introspection.py b/django/db/backends/base/introspection.py
index d20bfa1df0..5f828b94cc 100644
--- a/django/db/backends/base/introspection.py
+++ b/django/db/backends/base/introspection.py
@@ -2,7 +2,6 @@ from collections import namedtuple
 
 from django.utils import six
 
-
 # Structure returned by DatabaseIntrospection.get_table_list()
 TableInfo = namedtuple('TableInfo', ['name', 'type'])
 
diff --git a/django/db/backends/base/operations.py b/django/db/backends/base/operations.py
index f535a8792d..870edde382 100644
--- a/django/db/backends/base/operations.py
+++ b/django/db/backends/base/operations.py
@@ -1,7 +1,7 @@
 import datetime
 import decimal
-from importlib import import_module
 import warnings
+from importlib import import_module
 
 from django.conf import settings
 from django.db.backends import utils
diff --git a/django/db/backends/dummy/base.py b/django/db/backends/dummy/base.py
index e39d7e621e..ba8ad10210 100644
--- a/django/db/backends/dummy/base.py
+++ b/django/db/backends/dummy/base.py
@@ -12,8 +12,8 @@ from django.db.backends.base.base import BaseDatabaseWrapper
 from django.db.backends.base.client import BaseDatabaseClient
 from django.db.backends.base.creation import BaseDatabaseCreation
 from django.db.backends.base.features import BaseDatabaseFeatures
-from django.db.backends.base.operations import BaseDatabaseOperations
 from django.db.backends.base.introspection import BaseDatabaseIntrospection
+from django.db.backends.base.operations import BaseDatabaseOperations
 from django.db.backends.base.validation import BaseDatabaseValidation
 
 
diff --git a/django/db/backends/mysql/base.py b/django/db/backends/mysql/base.py
index f3413f43f3..f31697dadc 100644
--- a/django/db/backends/mysql/base.py
+++ b/django/db/backends/mysql/base.py
@@ -15,9 +15,8 @@ from django.conf import settings
 from django.db import utils
 from django.db.backends import utils as backend_utils
 from django.db.backends.base.base import BaseDatabaseWrapper
-from django.utils.encoding import force_str
-from django.db.backends.mysql.schema import DatabaseSchemaEditor
 from django.utils import six, timezone
+from django.utils.encoding import force_str
 from django.utils.functional import cached_property
 from django.utils.safestring import SafeBytes, SafeText
 
@@ -27,16 +26,17 @@ except ImportError as e:
     from django.core.exceptions import ImproperlyConfigured
     raise ImproperlyConfigured("Error loading MySQLdb module: %s" % e)
 
-from MySQLdb.converters import conversions, Thing2Literal
-from MySQLdb.constants import FIELD_TYPE, CLIENT
+from MySQLdb.constants import CLIENT, FIELD_TYPE                # isort:skip
+from MySQLdb.converters import Thing2Literal, conversions       # isort:skip
 
 # Some of these import MySQLdb, so import them after checking if it's installed.
-from .client import DatabaseClient
-from .creation import DatabaseCreation
-from .features import DatabaseFeatures
-from .introspection import DatabaseIntrospection
-from .operations import DatabaseOperations
-from .validation import DatabaseValidation
+from .client import DatabaseClient                          # isort:skip
+from .creation import DatabaseCreation                      # isort:skip
+from .features import DatabaseFeatures                      # isort:skip
+from .introspection import DatabaseIntrospection            # isort:skip
+from .operations import DatabaseOperations                  # isort:skip
+from .schema import DatabaseSchemaEditor                    # isort:skip
+from .validation import DatabaseValidation                  # isort:skip
 
 # We want version (1, 2, 1, 'final', 2) or later. We can't just use
 # lexicographic ordering in this check because then (1, 2, 1, 'gamma')
diff --git a/django/db/backends/mysql/introspection.py b/django/db/backends/mysql/introspection.py
index dc78a00bfc..8e07457aee 100644
--- a/django/db/backends/mysql/introspection.py
+++ b/django/db/backends/mysql/introspection.py
@@ -1,14 +1,14 @@
-from collections import namedtuple
 import re
+from collections import namedtuple
+
+from MySQLdb.constants import FIELD_TYPE
 
-from django.utils.datastructures import OrderedSet
 from django.db.backends.base.introspection import (
     BaseDatabaseIntrospection, FieldInfo, TableInfo,
 )
+from django.utils.datastructures import OrderedSet
 from django.utils.encoding import force_text
 
-from MySQLdb.constants import FIELD_TYPE
-
 FieldInfo = namedtuple('FieldInfo', FieldInfo._fields + ('extra',))
 
 foreign_key_re = re.compile(r"\sCONSTRAINT `[^`]*` FOREIGN KEY \(`([^`]*)`\) REFERENCES `([^`]*)` \(`([^`]*)`\)")
diff --git a/django/db/backends/oracle/base.py b/django/db/backends/oracle/base.py
index 134321cecc..d79b582e82 100644
--- a/django/db/backends/oracle/base.py
+++ b/django/db/backends/oracle/base.py
@@ -55,13 +55,13 @@ except ImportError as e:
     raise ImproperlyConfigured("Error loading cx_Oracle module: %s" % e)
 
 # Some of these import cx_Oracle, so import them after checking if it's installed.
-from .client import DatabaseClient
-from .creation import DatabaseCreation
-from .features import DatabaseFeatures
-from .introspection import DatabaseIntrospection
-from .operations import DatabaseOperations
-from .schema import DatabaseSchemaEditor
-from .utils import convert_unicode, Oracle_datetime
+from .client import DatabaseClient                          # isort:skip
+from .creation import DatabaseCreation                      # isort:skip
+from .features import DatabaseFeatures                      # isort:skip
+from .introspection import DatabaseIntrospection            # isort:skip
+from .operations import DatabaseOperations                  # isort:skip
+from .schema import DatabaseSchemaEditor                    # isort:skip
+from .utils import Oracle_datetime, convert_unicode         # isort:skip
 
 DatabaseError = Database.DatabaseError
 IntegrityError = Database.IntegrityError
diff --git a/django/db/backends/oracle/creation.py b/django/db/backends/oracle/creation.py
index de9de2c5b1..1e999f8358 100644
--- a/django/db/backends/oracle/creation.py
+++ b/django/db/backends/oracle/creation.py
@@ -6,7 +6,6 @@ from django.db.backends.base.creation import BaseDatabaseCreation
 from django.db.utils import DatabaseError
 from django.utils.six.moves import input
 
-
 TEST_DATABASE_PREFIX = 'test_'
 PASSWORD = 'Im_a_lumberjack'
 
diff --git a/django/db/backends/oracle/operations.py b/django/db/backends/oracle/operations.py
index fe9c93ba90..1ba49909d8 100644
--- a/django/db/backends/oracle/operations.py
+++ b/django/db/backends/oracle/operations.py
@@ -11,7 +11,7 @@ from django.utils import six, timezone
 from django.utils.encoding import force_bytes, force_text
 
 from .base import Database
-from .utils import convert_unicode, InsertIdVar, Oracle_datetime
+from .utils import InsertIdVar, Oracle_datetime, convert_unicode
 
 
 class DatabaseOperations(BaseDatabaseOperations):
diff --git a/django/db/backends/oracle/schema.py b/django/db/backends/oracle/schema.py
index 6b1dcf5343..fa710dc443 100644
--- a/django/db/backends/oracle/schema.py
+++ b/django/db/backends/oracle/schema.py
@@ -1,11 +1,11 @@
+import binascii
 import copy
 import datetime
-import binascii
 
-from django.utils import six
-from django.utils.text import force_text
 from django.db.backends.base.schema import BaseDatabaseSchemaEditor
 from django.db.utils import DatabaseError
+from django.utils import six
+from django.utils.text import force_text
 
 
 class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
diff --git a/django/db/backends/postgresql_psycopg2/base.py b/django/db/backends/postgresql_psycopg2/base.py
index a73d1f27bf..4410a173a0 100644
--- a/django/db/backends/postgresql_psycopg2/base.py
+++ b/django/db/backends/postgresql_psycopg2/base.py
@@ -9,7 +9,7 @@ from django.db.backends.base.base import BaseDatabaseWrapper
 from django.db.backends.base.validation import BaseDatabaseValidation
 from django.utils.encoding import force_str
 from django.utils.functional import cached_property
-from django.utils.safestring import SafeText, SafeBytes
+from django.utils.safestring import SafeBytes, SafeText
 
 try:
     import psycopg2 as Database
@@ -20,14 +20,14 @@ except ImportError as e:
     raise ImproperlyConfigured("Error loading psycopg2 module: %s" % e)
 
 # Some of these import psycopg2, so import them after checking if it's installed.
-from .client import DatabaseClient
-from .creation import DatabaseCreation
-from .features import DatabaseFeatures
-from .introspection import DatabaseIntrospection
-from .operations import DatabaseOperations
-from .schema import DatabaseSchemaEditor
-from .utils import utc_tzinfo_factory
-from .version import get_version
+from .client import DatabaseClient                          # isort:skip
+from .creation import DatabaseCreation                      # isort:skip
+from .features import DatabaseFeatures                      # isort:skip
+from .introspection import DatabaseIntrospection            # isort:skip
+from .operations import DatabaseOperations                  # isort:skip
+from .schema import DatabaseSchemaEditor                    # isort:skip
+from .utils import utc_tzinfo_factory                       # isort:skip
+from .version import get_version                            # isort:skip
 
 DatabaseError = Database.DatabaseError
 IntegrityError = Database.IntegrityError
diff --git a/django/db/backends/postgresql_psycopg2/introspection.py b/django/db/backends/postgresql_psycopg2/introspection.py
index 7236f5121f..32c69bc510 100644
--- a/django/db/backends/postgresql_psycopg2/introspection.py
+++ b/django/db/backends/postgresql_psycopg2/introspection.py
@@ -1,4 +1,5 @@
 from __future__ import unicode_literals
+
 from collections import namedtuple
 
 from django.db.backends.base.introspection import (
@@ -6,7 +7,6 @@ from django.db.backends.base.introspection import (
 )
 from django.utils.encoding import force_text
 
-
 FieldInfo = namedtuple('FieldInfo', FieldInfo._fields + ('default',))
 
 
diff --git a/django/db/backends/postgresql_psycopg2/operations.py b/django/db/backends/postgresql_psycopg2/operations.py
index 27b19db459..e9dd58a344 100644
--- a/django/db/backends/postgresql_psycopg2/operations.py
+++ b/django/db/backends/postgresql_psycopg2/operations.py
@@ -1,10 +1,10 @@
 from __future__ import unicode_literals
 
+from psycopg2.extras import Inet
+
 from django.conf import settings
 from django.db.backends.base.operations import BaseDatabaseOperations
 
-from psycopg2.extras import Inet
-
 
 class DatabaseOperations(BaseDatabaseOperations):
     def unification_cast_sql(self, output_field):
diff --git a/django/db/backends/postgresql_psycopg2/schema.py b/django/db/backends/postgresql_psycopg2/schema.py
index c75123a349..8340059b26 100644
--- a/django/db/backends/postgresql_psycopg2/schema.py
+++ b/django/db/backends/postgresql_psycopg2/schema.py
@@ -1,7 +1,7 @@
-from django.db.backends.base.schema import BaseDatabaseSchemaEditor
-
 import psycopg2
 
+from django.db.backends.base.schema import BaseDatabaseSchemaEditor
+
 
 class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
 
diff --git a/django/db/backends/sqlite3/base.py b/django/db/backends/sqlite3/base.py
index a71bae99b2..84d24e5bfe 100644
--- a/django/db/backends/sqlite3/base.py
+++ b/django/db/backends/sqlite3/base.py
@@ -36,13 +36,13 @@ except ImportError as exc:
     raise ImproperlyConfigured("Error loading either pysqlite2 or sqlite3 modules (tried in that order): %s" % exc)
 
 # Some of these import sqlite3, so import them after checking if it's installed.
-from .client import DatabaseClient
-from .creation import DatabaseCreation
-from .features import DatabaseFeatures
-from .introspection import DatabaseIntrospection
-from .operations import DatabaseOperations
-from .schema import DatabaseSchemaEditor
-from .utils import parse_datetime_with_timezone_support
+from .client import DatabaseClient                          # isort:skip
+from .creation import DatabaseCreation                      # isort:skip
+from .features import DatabaseFeatures                      # isort:skip
+from .introspection import DatabaseIntrospection            # isort:skip
+from .operations import DatabaseOperations                  # isort:skip
+from .schema import DatabaseSchemaEditor                    # isort:skip
+from .utils import parse_datetime_with_timezone_support     # isort:skip
 
 DatabaseError = Database.DatabaseError
 IntegrityError = Database.IntegrityError
diff --git a/django/db/backends/sqlite3/introspection.py b/django/db/backends/sqlite3/introspection.py
index 13b658bd6a..a035695653 100644
--- a/django/db/backends/sqlite3/introspection.py
+++ b/django/db/backends/sqlite3/introspection.py
@@ -4,7 +4,6 @@ from django.db.backends.base.introspection import (
     BaseDatabaseIntrospection, FieldInfo, TableInfo,
 )
 
-
 field_size_re = re.compile(r'^\s*(?:var)?char\s*\(\s*(\d+)\s*\)\s*$')
 
 
diff --git a/django/db/backends/sqlite3/operations.py b/django/db/backends/sqlite3/operations.py
index cd29092cd7..5d974f36df 100644
--- a/django/db/backends/sqlite3/operations.py
+++ b/django/db/backends/sqlite3/operations.py
@@ -4,14 +4,14 @@ import datetime
 import uuid
 
 from django.conf import settings
-from django.core.exceptions import ImproperlyConfigured, FieldError
+from django.core.exceptions import FieldError, ImproperlyConfigured
 from django.db import utils
 from django.db.backends import utils as backend_utils
 from django.db.backends.base.operations import BaseDatabaseOperations
-from django.db.models import fields, aggregates
+from django.db.models import aggregates, fields
+from django.utils import six, timezone
 from django.utils.dateparse import parse_date, parse_time
 from django.utils.duration import duration_string
-from django.utils import six, timezone
 
 from .utils import parse_datetime_with_timezone_support
 
diff --git a/django/db/backends/sqlite3/schema.py b/django/db/backends/sqlite3/schema.py
index 031bf77840..0d101b0f27 100644
--- a/django/db/backends/sqlite3/schema.py
+++ b/django/db/backends/sqlite3/schema.py
@@ -2,12 +2,12 @@ import codecs
 import copy
 from decimal import Decimal
 
+import _sqlite3
+
 from django.apps.registry import Apps
 from django.db.backends.base.schema import BaseDatabaseSchemaEditor
 from django.utils import six
 
-import _sqlite3
-
 
 class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
 
diff --git a/django/db/backends/util.py b/django/db/backends/util.py
index 5797830974..7a2c4aaf4a 100644
--- a/django/db/backends/util.py
+++ b/django/db/backends/util.py
@@ -7,4 +7,4 @@ warnings.warn(
     "Use django.db.backends.utils instead.", RemovedInDjango19Warning,
     stacklevel=2)
 
-from django.db.backends.utils import *  # NOQA
+from django.db.backends.utils import *  # NOQA isort:skip
diff --git a/django/db/backends/utils.py b/django/db/backends/utils.py
index 7aa0cfdad5..84444548d3 100644
--- a/django/db/backends/utils.py
+++ b/django/db/backends/utils.py
@@ -10,7 +10,6 @@ from django.conf import settings
 from django.utils.encoding import force_bytes
 from django.utils.timezone import utc
 
-
 logger = logging.getLogger('django.db.backends')
 
 
diff --git a/django/db/migrations/autodetector.py b/django/db/migrations/autodetector.py
index e86e9c5f68..16df9bfd91 100644
--- a/django/db/migrations/autodetector.py
+++ b/django/db/migrations/autodetector.py
@@ -1,18 +1,17 @@
 from __future__ import unicode_literals
 
-import re
 import datetime
-
+import re
 from itertools import chain
 
-from django.utils import six
 from django.conf import settings
 from django.db import models
 from django.db.migrations import operations
 from django.db.migrations.migration import Migration
-from django.db.migrations.questioner import MigrationQuestioner
-from django.db.migrations.optimizer import MigrationOptimizer
 from django.db.migrations.operations.models import AlterModelOptions
+from django.db.migrations.optimizer import MigrationOptimizer
+from django.db.migrations.questioner import MigrationQuestioner
+from django.utils import six
 
 from .topological_sort import stable_topological_sort
 
diff --git a/django/db/migrations/executor.py b/django/db/migrations/executor.py
index cc38758f5a..8a55ed0d69 100644
--- a/django/db/migrations/executor.py
+++ b/django/db/migrations/executor.py
@@ -1,7 +1,8 @@
 from __future__ import unicode_literals
 
-from django.db import migrations
 from django.apps.registry import apps as global_apps
+from django.db import migrations
+
 from .loader import MigrationLoader
 from .recorder import MigrationRecorder
 from .state import ProjectState
diff --git a/django/db/migrations/graph.py b/django/db/migrations/graph.py
index 0e3c5905d6..bf4d6b5252 100644
--- a/django/db/migrations/graph.py
+++ b/django/db/migrations/graph.py
@@ -1,4 +1,5 @@
 from __future__ import unicode_literals
+
 from collections import deque
 
 from django.db.migrations.state import ProjectState
diff --git a/django/db/migrations/loader.py b/django/db/migrations/loader.py
index ce6849f280..add2907ca8 100644
--- a/django/db/migrations/loader.py
+++ b/django/db/migrations/loader.py
@@ -1,8 +1,8 @@
 from __future__ import unicode_literals
 
-from importlib import import_module
 import os
 import sys
+from importlib import import_module
 
 from django.apps import apps
 from django.conf import settings
@@ -10,7 +10,6 @@ from django.db.migrations.graph import MigrationGraph, NodeNotFoundError
 from django.db.migrations.recorder import MigrationRecorder
 from django.utils import six
 
-
 MIGRATIONS_MODULE_NAME = 'migrations'
 
 
diff --git a/django/db/migrations/migration.py b/django/db/migrations/migration.py
index 71e662db67..1c3f560d6e 100644
--- a/django/db/migrations/migration.py
+++ b/django/db/migrations/migration.py
@@ -1,4 +1,5 @@
 from __future__ import unicode_literals
+
 from django.db.transaction import atomic
 from django.utils.encoding import python_2_unicode_compatible
 
diff --git a/django/db/migrations/operations/base.py b/django/db/migrations/operations/base.py
index 04089938c2..557c956732 100644
--- a/django/db/migrations/operations/base.py
+++ b/django/db/migrations/operations/base.py
@@ -1,4 +1,5 @@
 from __future__ import unicode_literals
+
 from django.db import router
 
 
diff --git a/django/db/migrations/operations/fields.py b/django/db/migrations/operations/fields.py
index ea9dffff1f..70e7a0f296 100644
--- a/django/db/migrations/operations/fields.py
+++ b/django/db/migrations/operations/fields.py
@@ -3,6 +3,7 @@ from __future__ import unicode_literals
 from django.db.models.fields import NOT_PROVIDED
 from django.utils import six
 from django.utils.functional import cached_property
+
 from .base import Operation
 
 
diff --git a/django/db/migrations/operations/models.py b/django/db/migrations/operations/models.py
index cdc3c06e50..99df8a073e 100644
--- a/django/db/migrations/operations/models.py
+++ b/django/db/migrations/operations/models.py
@@ -1,9 +1,9 @@
 from __future__ import unicode_literals
 
 from django.db import models
-from django.db.models.options import normalize_together
-from django.db.migrations.state import ModelState
 from django.db.migrations.operations.base import Operation
+from django.db.migrations.state import ModelState
+from django.db.models.options import normalize_together
 from django.utils import six
 from django.utils.functional import cached_property
 
diff --git a/django/db/migrations/state.py b/django/db/migrations/state.py
index 7eb1e5b8b9..2e2fbaa0f8 100644
--- a/django/db/migrations/state.py
+++ b/django/db/migrations/state.py
@@ -1,14 +1,15 @@
 from __future__ import unicode_literals
-from collections import OrderedDict
+
 import copy
+from collections import OrderedDict
 
 from django.apps import AppConfig
 from django.apps.registry import Apps, apps as global_apps
+from django.conf import settings
 from django.db import models
-from django.db.models.options import DEFAULT_NAMES, normalize_together
-from django.db.models.fields.related import do_pending_lookups
 from django.db.models.fields.proxy import OrderWrt
-from django.conf import settings
+from django.db.models.fields.related import do_pending_lookups
+from django.db.models.options import DEFAULT_NAMES, normalize_together
 from django.utils import six
 from django.utils.encoding import force_text, smart_text
 from django.utils.functional import cached_property
diff --git a/django/db/migrations/writer.py b/django/db/migrations/writer.py
index 6d77c6121a..bf4e62d255 100644
--- a/django/db/migrations/writer.py
+++ b/django/db/migrations/writer.py
@@ -3,16 +3,16 @@ from __future__ import unicode_literals
 import collections
 import datetime
 import decimal
-from importlib import import_module
 import inspect
 import math
 import os
 import re
 import sys
 import types
+from importlib import import_module
 
 from django.apps import apps
-from django.db import models, migrations
+from django.db import migrations, models
 from django.db.migrations.loader import MigrationLoader
 from django.utils import datetime_safe, six
 from django.utils.encoding import force_text
@@ -20,7 +20,6 @@ from django.utils.functional import Promise
 from django.utils.timezone import utc
 from django.utils.version import get_docs_version
 
-
 COMPILED_REGEX_TYPE = type(re.compile(''))
 
 
diff --git a/django/db/models/aggregates.py b/django/db/models/aggregates.py
index c1ddc75d4c..01ab61f71a 100644
--- a/django/db/models/aggregates.py
+++ b/django/db/models/aggregates.py
@@ -3,7 +3,7 @@ Classes to represent the definitions of aggregate functions.
 """
 from django.core.exceptions import FieldError
 from django.db.models.expressions import Func, Value
-from django.db.models.fields import IntegerField, FloatField
+from django.db.models.fields import FloatField, IntegerField
 
 __all__ = [
     'Aggregate', 'Avg', 'Count', 'Max', 'Min', 'StdDev', 'Sum', 'Variance',
diff --git a/django/db/models/deletion.py b/django/db/models/deletion.py
index 016fc5637e..431b15b0ef 100644
--- a/django/db/models/deletion.py
+++ b/django/db/models/deletion.py
@@ -2,7 +2,7 @@ from collections import OrderedDict
 from itertools import chain
 from operator import attrgetter
 
-from django.db import connections, transaction, IntegrityError
+from django.db import IntegrityError, connections, transaction
 from django.db.models import signals, sql
 from django.utils import six
 
diff --git a/django/db/models/expressions.py b/django/db/models/expressions.py
index 87a08ecc3b..c15b095bc2 100644
--- a/django/db/models/expressions.py
+++ b/django/db/models/expressions.py
@@ -6,7 +6,7 @@ from django.core.exceptions import FieldError
 from django.db.backends import utils as backend_utils
 from django.db.models import fields
 from django.db.models.constants import LOOKUP_SEP
-from django.db.models.query_utils import refs_aggregate, Q
+from django.db.models.query_utils import Q, refs_aggregate
 from django.utils import timezone
 from django.utils.functional import cached_property
 
diff --git a/django/db/models/fields/files.py b/django/db/models/fields/files.py
index 301244bbef..5eb6e7845f 100644
--- a/django/db/models/fields/files.py
+++ b/django/db/models/fields/files.py
@@ -1,19 +1,19 @@
 import datetime
-from inspect import getargspec
 import os
 import warnings
+from inspect import getargspec
 
 from django import forms
-from django.db.models.fields import Field
 from django.core import checks
 from django.core.files.base import File
-from django.core.files.storage import default_storage
 from django.core.files.images import ImageFile
+from django.core.files.storage import default_storage
 from django.db.models import signals
-from django.utils.encoding import force_str, force_text
+from django.db.models.fields import Field
 from django.utils import six
-from django.utils.translation import ugettext_lazy as _
 from django.utils.deprecation import RemovedInDjango20Warning
+from django.utils.encoding import force_str, force_text
+from django.utils.translation import ugettext_lazy as _
 
 
 class FieldFile(File):
diff --git a/django/db/models/fields/related.py b/django/db/models/fields/related.py
index 8acae08efb..922d8b4bd0 100644
--- a/django/db/models/fields/related.py
+++ b/django/db/models/fields/related.py
@@ -1,27 +1,28 @@
 from __future__ import unicode_literals
 
-from operator import attrgetter
 import warnings
+from operator import attrgetter
 
+from django import forms
 from django.apps import apps
-from django.core import checks
+from django.core import checks, exceptions
 from django.core.exceptions import FieldDoesNotExist
 from django.db import connection, connections, router, transaction
 from django.db.backends import utils
-from django.db.models import signals, Q
-from django.db.models.deletion import SET_NULL, SET_DEFAULT, CASCADE
-from django.db.models.fields import (AutoField, Field, IntegerField,
-    PositiveIntegerField, PositiveSmallIntegerField, BLANK_CHOICE_DASH)
+from django.db.models import Q, signals
+from django.db.models.deletion import CASCADE, SET_DEFAULT, SET_NULL
+from django.db.models.fields import (
+    BLANK_CHOICE_DASH, AutoField, Field, IntegerField, PositiveIntegerField,
+    PositiveSmallIntegerField,
+)
 from django.db.models.lookups import IsNull
 from django.db.models.query import QuerySet
 from django.db.models.query_utils import PathInfo
-from django.utils.encoding import force_text, smart_text
 from django.utils import six
 from django.utils.deprecation import RemovedInDjango20Warning
+from django.utils.encoding import force_text, smart_text
+from django.utils.functional import cached_property, curry
 from django.utils.translation import ugettext_lazy as _
-from django.utils.functional import curry, cached_property
-from django.core import exceptions
-from django import forms
 
 RECURSIVE_RELATIONSHIP_CONSTANT = 'self'
 
diff --git a/django/db/models/loading.py b/django/db/models/loading.py
index 82cb2dc4da..32526533b3 100644
--- a/django/db/models/loading.py
+++ b/django/db/models/loading.py
@@ -3,7 +3,6 @@ import warnings
 from django.apps import apps
 from django.utils.deprecation import RemovedInDjango19Warning
 
-
 warnings.warn(
     "The utilities in django.db.models.loading are deprecated "
     "in favor of the new application loading system.",
diff --git a/django/db/models/lookups.py b/django/db/models/lookups.py
index 7610c0dde4..9a966bfc1b 100644
--- a/django/db/models/lookups.py
+++ b/django/db/models/lookups.py
@@ -1,5 +1,5 @@
-from copy import copy
 import inspect
+from copy import copy
 
 from django.conf import settings
 from django.utils import timezone
diff --git a/django/db/models/manager.py b/django/db/models/manager.py
index aa2df3f0e8..e194e28feb 100644
--- a/django/db/models/manager.py
+++ b/django/db/models/manager.py
@@ -1,6 +1,6 @@
 import copy
-from importlib import import_module
 import inspect
+from importlib import import_module
 
 from django.db import router
 from django.db.models.query import QuerySet
diff --git a/django/db/models/options.py b/django/db/models/options.py
index fa9726556b..83f1eb036a 100644
--- a/django/db/models/options.py
+++ b/django/db/models/options.py
@@ -1,20 +1,22 @@
 from __future__ import unicode_literals
 
+import warnings
 from bisect import bisect
 from collections import OrderedDict, defaultdict
 from itertools import chain
-import warnings
 
 from django.apps import apps
 from django.conf import settings
 from django.core.exceptions import FieldDoesNotExist
-from django.db.models.fields.related import ManyToManyField
 from django.db.models.fields import AutoField
 from django.db.models.fields.proxy import OrderWrt
+from django.db.models.fields.related import ManyToManyField
 from django.utils import six
 from django.utils.datastructures import ImmutableList, OrderedSet
 from django.utils.deprecation import RemovedInDjango20Warning
-from django.utils.encoding import force_text, smart_text, python_2_unicode_compatible
+from django.utils.encoding import (
+    force_text, python_2_unicode_compatible, smart_text,
+)
 from django.utils.functional import cached_property
 from django.utils.lru_cache import lru_cache
 from django.utils.text import camel_case_to_spaces
diff --git a/django/db/models/query.py b/django/db/models/query.py
index 2b7aab6ac4..0ec3cfd730 100644
--- a/django/db/models/query.py
+++ b/django/db/models/query.py
@@ -2,25 +2,28 @@
 The main QuerySet implementation. This provides the public API for the ORM.
 """
 
-from collections import deque, OrderedDict
 import copy
 import sys
 import warnings
+from collections import OrderedDict, deque
 
 from django.conf import settings
 from django.core import exceptions
-from django.db import (connections, router, transaction, IntegrityError,
-    DJANGO_VERSION_PICKLE_KEY)
+from django.db import (
+    DJANGO_VERSION_PICKLE_KEY, IntegrityError, connections, router,
+    transaction,
+)
+from django.db.models import sql
 from django.db.models.constants import LOOKUP_SEP
-from django.db.models.fields import AutoField, Empty
-from django.db.models.query_utils import Q, deferred_class_factory, InvalidQuery
 from django.db.models.deletion import Collector
+from django.db.models.expressions import F, Date, DateTime
+from django.db.models.fields import AutoField, Empty
+from django.db.models.query_utils import (
+    Q, InvalidQuery, deferred_class_factory,
+)
 from django.db.models.sql.constants import CURSOR
-from django.db.models import sql
-from django.db.models.expressions import Date, DateTime, F
+from django.utils import six, timezone
 from django.utils.functional import partition
-from django.utils import six
-from django.utils import timezone
 from django.utils.version import get_version
 
 # The maximum number of items to display in a QuerySet.__repr__
diff --git a/django/db/models/query_utils.py b/django/db/models/query_utils.py
index 7751f988db..10580f77a6 100644
--- a/django/db/models/query_utils.py
+++ b/django/db/models/query_utils.py
@@ -13,9 +13,7 @@ from django.apps import apps
 from django.core.exceptions import FieldDoesNotExist
 from django.db.backends import utils
 from django.db.models.constants import LOOKUP_SEP
-from django.utils import six
-from django.utils import tree
-
+from django.utils import six, tree
 
 # PathInfo is used when converting lookups (fk__somecol). The contents
 # describe the relation in Model terms (model Options and Fields for both
diff --git a/django/db/models/sql/aggregates.py b/django/db/models/sql/aggregates.py
index 713f530a91..0ebe10e83f 100644
--- a/django/db/models/sql/aggregates.py
+++ b/django/db/models/sql/aggregates.py
@@ -4,12 +4,11 @@ Classes to represent the default SQL aggregate functions
 import copy
 import warnings
 
-from django.db.models.fields import IntegerField, FloatField
+from django.db.models.fields import FloatField, IntegerField
 from django.db.models.lookups import RegisterLookupMixin
 from django.utils.deprecation import RemovedInDjango20Warning
 from django.utils.functional import cached_property
 
-
 __all__ = ['Aggregate', 'Avg', 'Count', 'Max', 'Min', 'StdDev', 'Sum', 'Variance']
 
 
diff --git a/django/db/models/sql/compiler.py b/django/db/models/sql/compiler.py
index 8f3af37031..5c1dcf4f05 100644
--- a/django/db/models/sql/compiler.py
+++ b/django/db/models/sql/compiler.py
@@ -1,15 +1,16 @@
-from itertools import chain
 import re
 import warnings
+from itertools import chain
 
 from django.core.exceptions import FieldError
 from django.db.models.constants import LOOKUP_SEP
 from django.db.models.expressions import OrderBy, Random, RawSQL, Ref
-from django.db.models.query_utils import select_related_descend, QueryWrapper
-from django.db.models.sql.constants import (CURSOR, SINGLE, MULTI, NO_RESULTS,
-        ORDER_DIR, GET_ITERATOR_CHUNK_SIZE)
+from django.db.models.query_utils import QueryWrapper, select_related_descend
+from django.db.models.sql.constants import (
+    CURSOR, GET_ITERATOR_CHUNK_SIZE, MULTI, NO_RESULTS, ORDER_DIR, SINGLE,
+)
 from django.db.models.sql.datastructures import EmptyResultSet
-from django.db.models.sql.query import get_order_dir, Query
+from django.db.models.sql.query import Query, get_order_dir
 from django.db.transaction import TransactionManagementError
 from django.db.utils import DatabaseError
 from django.utils.deprecation import RemovedInDjango20Warning
diff --git a/django/db/models/sql/query.py b/django/db/models/sql/query.py
index 4fb22149d0..f99b58b84f 100644
--- a/django/db/models/sql/query.py
+++ b/django/db/models/sql/query.py
@@ -6,28 +6,31 @@ themselves do not have to (and could be backed by things other than SQL
 databases). The abstraction barrier only works one way: this module has to know
 all about the internals of models in order to get the information it needs.
 """
-from string import ascii_uppercase
-from itertools import count, product
-
-from collections import Mapping, OrderedDict
 import copy
-from itertools import chain
 import warnings
+from collections import Mapping, OrderedDict
+from itertools import chain, count, product
+from string import ascii_uppercase
 
 from django.core.exceptions import FieldDoesNotExist, FieldError
-from django.db import connections, DEFAULT_DB_ALIAS
+from django.db import DEFAULT_DB_ALIAS, connections
 from django.db.models.aggregates import Count
 from django.db.models.constants import LOOKUP_SEP
 from django.db.models.expressions import Col, Ref
-from django.db.models.query_utils import PathInfo, Q, refs_aggregate
-from django.db.models.sql.constants import (QUERY_TERMS, ORDER_DIR, SINGLE,
-        ORDER_PATTERN, INNER, LOUTER)
+from django.db.models.query_utils import Q, PathInfo, refs_aggregate
+from django.db.models.sql.constants import (
+    INNER, LOUTER, ORDER_DIR, ORDER_PATTERN, QUERY_TERMS, SINGLE,
+)
 from django.db.models.sql.datastructures import (
-    EmptyResultSet, Empty, MultiJoin, Join, BaseTable)
-from django.db.models.sql.where import (WhereNode, Constraint, EverythingNode,
-    ExtraWhere, AND, OR, EmptyWhere)
+    BaseTable, Empty, EmptyResultSet, Join, MultiJoin,
+)
+from django.db.models.sql.where import (
+    AND, OR, Constraint, EmptyWhere, EverythingNode, ExtraWhere, WhereNode,
+)
 from django.utils import six
-from django.utils.deprecation import RemovedInDjango19Warning, RemovedInDjango20Warning
+from django.utils.deprecation import (
+    RemovedInDjango19Warning, RemovedInDjango20Warning,
+)
 from django.utils.encoding import force_text
 from django.utils.tree import Node
 
diff --git a/django/db/models/sql/subqueries.py b/django/db/models/sql/subqueries.py
index be7438b2a7..78c13816d1 100644
--- a/django/db/models/sql/subqueries.py
+++ b/django/db/models/sql/subqueries.py
@@ -9,7 +9,6 @@ from django.db.models.sql.constants import GET_ITERATOR_CHUNK_SIZE, NO_RESULTS
 from django.db.models.sql.query import Query
 from django.utils import six
 
-
 __all__ = ['DeleteQuery', 'UpdateQuery', 'InsertQuery', 'AggregateQuery']
 
 
diff --git a/django/db/models/sql/where.py b/django/db/models/sql/where.py
index 6a03210a93..2ba6ceac33 100644
--- a/django/db/models/sql/where.py
+++ b/django/db/models/sql/where.py
@@ -4,18 +4,16 @@ Code to manage the creation and SQL rendering of 'where' constraints.
 
 import collections
 import datetime
-from itertools import repeat
 import warnings
+from itertools import repeat
 
 from django.conf import settings
 from django.db.models.fields import DateTimeField, Field
-from django.db.models.sql.datastructures import EmptyResultSet, Empty
+from django.db.models.sql.datastructures import Empty, EmptyResultSet
+from django.utils import timezone, tree
 from django.utils.deprecation import RemovedInDjango19Warning
 from django.utils.functional import cached_property
 from django.utils.six.moves import range
-from django.utils import timezone
-from django.utils import tree
-
 
 # Connection types
 AND = 'AND'
diff --git a/django/db/transaction.py b/django/db/transaction.py
index 6d2bff52f4..d1388675d5 100644
--- a/django/db/transaction.py
+++ b/django/db/transaction.py
@@ -1,6 +1,6 @@
 from django.db import (
-    connections, DEFAULT_DB_ALIAS,
-    DatabaseError, Error, ProgrammingError)
+    DEFAULT_DB_ALIAS, DatabaseError, Error, ProgrammingError, connections,
+)
 from django.utils.decorators import ContextDecorator
 
 
diff --git a/django/db/utils.py b/django/db/utils.py
index fc2203ff47..0f5fecdcff 100644
--- a/django/db/utils.py
+++ b/django/db/utils.py
@@ -1,17 +1,16 @@
-from importlib import import_module
 import os
 import pkgutil
-from threading import local
 import warnings
+from importlib import import_module
+from threading import local
 
 from django.conf import settings
 from django.core.exceptions import ImproperlyConfigured
+from django.utils import six
+from django.utils._os import upath
 from django.utils.deprecation import RemovedInDjango19Warning
 from django.utils.functional import cached_property
 from django.utils.module_loading import import_string
-from django.utils._os import upath
-from django.utils import six
-
 
 DEFAULT_DB_ALIAS = 'default'
 DJANGO_VERSION_PICKLE_KEY = '_django_version'