1 files changed, 9 insertions, 3 deletions
diff --git a/tests/m2o_recursive/models.py b/tests/m2o_recursive/models.py
index bb73589800..af23588456 100644
--- a/tests/m2o_recursive/models.py
+++ b/tests/m2o_recursive/models.py
@@ -15,7 +15,9 @@ from django.db import models
 
 class Category(models.Model):
     name = models.CharField(max_length=20)
-    parent = models.ForeignKey('self', models.SET_NULL, blank=True, null=True, related_name='child_set')
+    parent = models.ForeignKey(
+        "self", models.SET_NULL, blank=True, null=True, related_name="child_set"
+    )
 
     def __str__(self):
         return self.name
@@ -23,8 +25,12 @@ class Category(models.Model):
 
 class Person(models.Model):
     full_name = models.CharField(max_length=20)
-    mother = models.ForeignKey('self', models.SET_NULL, null=True, related_name='mothers_child_set')
-    father = models.ForeignKey('self', models.SET_NULL, null=True, related_name='fathers_child_set')
+    mother = models.ForeignKey(
+        "self", models.SET_NULL, null=True, related_name="mothers_child_set"
+    )
+    father = models.ForeignKey(
+        "self", models.SET_NULL, null=True, related_name="fathers_child_set"
+    )
 
     def __str__(self):
         return self.full_name