diff --git a/django/db/migrations/operations/base.py b/django/db/migrations/operations/base.py
index 8b8602e81a..8d09326fe1 100644
--- a/django/db/migrations/operations/base.py
+++ b/django/db/migrations/operations/base.py
@@ -10,7 +10,7 @@ class Operation(object):
     copying operations), and some will need their modifications to be
     optionally specified by the user (e.g. custom Python code snippets)
 
-    Due to the way this class deals with deconstruction, it should be 
+    Due to the way this class deals with deconstruction, it should be
     considered immutable.
     """
 
diff --git a/django/db/migrations/operations/fields.py b/django/db/migrations/operations/fields.py
index 5b687c6656..b609110f85 100644
--- a/django/db/migrations/operations/fields.py
+++ b/django/db/migrations/operations/fields.py
@@ -171,5 +171,5 @@ class RenameField(Operation):
     def references_field(self, model_name, name, app_label=None):
         return self.references_model(model_name) and (
             name.lower() == self.old_name.lower() or
-            name.lower() == self.new_name.lower() 
+            name.lower() == self.new_name.lower()
         )
diff --git a/django/db/migrations/optimizer.py b/django/db/migrations/optimizer.py
index b87dc29bdb..435ac6766e 100644
--- a/django/db/migrations/optimizer.py
+++ b/django/db/migrations/optimizer.py
@@ -178,9 +178,9 @@ class MigrationOptimizer(object):
         if operation.name.lower() == other.old_name.lower():
             return [migrations.CreateModel(
                 other.new_name,
-                fields = operation.fields,
-                options = operation.options,
-                bases = operation.bases,
+                fields=operation.fields,
+                options=operation.options,
+                bases=operation.bases,
             )]
 
     def reduce_model_rename_self(self, operation, other):
@@ -199,54 +199,54 @@ class MigrationOptimizer(object):
         if operation.name.lower() == other.model_name.lower():
             return [migrations.CreateModel(
                 operation.name,
-                fields = operation.fields + [(other.name, other.field)],
-                options = operation.options,
-                bases = operation.bases,
+                fields=operation.fields + [(other.name, other.field)],
+                options=operation.options,
+                bases=operation.bases,
             )]
 
     def reduce_create_model_alter_field(self, operation, other):
         if operation.name.lower() == other.model_name.lower():
             return [migrations.CreateModel(
                 operation.name,
-                fields = [
+                fields=[
                     (n, other.field if n == other.name else v)
                     for n, v in operation.fields
                 ],
-                options = operation.options,
-                bases = operation.bases,
+                options=operation.options,
+                bases=operation.bases,
             )]
 
     def reduce_create_model_rename_field(self, operation, other):
         if operation.name.lower() == other.model_name.lower():
             return [migrations.CreateModel(
                 operation.name,
-                fields = [
+                fields=[
                     (other.new_name if n == other.old_name else n, v)
                     for n, v in operation.fields
                 ],
-                options = operation.options,
-                bases = operation.bases,
+                options=operation.options,
+                bases=operation.bases,
             )]
 
     def reduce_create_model_remove_field(self, operation, other):
         if operation.name.lower() == other.model_name.lower():
             return [migrations.CreateModel(
                 operation.name,
-                fields = [
+                fields=[
                     (n, v)
                     for n, v in operation.fields
                     if n.lower() != other.name.lower()
                 ],
-                options = operation.options,
-                bases = operation.bases,
+                options=operation.options,
+                bases=operation.bases,
             )]
 
     def reduce_add_field_alter_field(self, operation, other):
         if operation.model_name.lower() == other.model_name.lower() and operation.name.lower() == other.name.lower():
             return [migrations.AddField(
-                model_name = operation.model_name,
-                name = operation.name,
-                field = other.field,
+                model_name=operation.model_name,
+                name=operation.name,
+                field=other.field,
             )]
 
     def reduce_add_field_delete_field(self, operation, other):
@@ -260,9 +260,9 @@ class MigrationOptimizer(object):
     def reduce_add_field_rename_field(self, operation, other):
         if operation.model_name.lower() == other.model_name.lower() and operation.name.lower() == other.old_name.lower():
             return [migrations.AddField(
-                model_name = operation.model_name,
-                name = other.new_name,
-                field = operation.field,
+                model_name=operation.model_name,
+                name=other.new_name,
+                field=operation.field,
             )]
 
     def reduce_alter_field_rename_field(self, operation, other):
@@ -270,9 +270,9 @@ class MigrationOptimizer(object):
             return [
                 other,
                 migrations.AlterField(
-                    model_name = operation.model_name,
-                    name = other.new_name,
-                    field = operation.field,
+                    model_name=operation.model_name,
+                    name=other.new_name,
+                    field=operation.field,
                 ),
             ]
 
diff --git a/django/utils/translation/trans_real.py b/django/utils/translation/trans_real.py
index 8a7a7fafff..e3081dd19a 100644
--- a/django/utils/translation/trans_real.py
+++ b/django/utils/translation/trans_real.py
@@ -49,7 +49,7 @@ accept_language_re = re.compile(r'''
 language_code_prefix_re = re.compile(r'^/([\w-]+)(/|$)')
 
 # some browsers use deprecated locales. refs #18419
-_BROWSERS_DEPRECATED_LOCALES  = {
+_BROWSERS_DEPRECATED_LOCALES = {
     'zh-cn': 'zh-hans',
     'zh-tw': 'zh-hant',
 }
diff --git a/tests/migrations/test_optimizer.py b/tests/migrations/test_optimizer.py
index 8ba42db467..b73c41a698 100644
--- a/tests/migrations/test_optimizer.py
+++ b/tests/migrations/test_optimizer.py
@@ -1,5 +1,5 @@
 # encoding: utf8
-import operator
+
 from django.test import TestCase
 from django.db.migrations.optimizer import MigrationOptimizer
 from django.db import migrations
@@ -65,7 +65,7 @@ class OptimizerTests(TestCase):
         self.assertOptimizesTo(
             [migrations.DeleteModel("Foo")],
             [migrations.DeleteModel("Foo")],
-            exact = 1,
+            exact=1,
         )
 
     def test_create_delete_model(self):