Removed unused imports + other flake8 fixes.

django/db/migrations/operations/special.py

 import re
-import textwrap
 from .base import Operation
-from django.utils import six
 
 
 class SeparateDatabaseAndState(Operation):

tests/decorators/tests.py

@@ -174,6 +174,7 @@ def myattr2_dec(func):
 
 myattr2_dec_m = method_decorator(myattr2_dec)
 
+
 class ClsDec(object):
     def __init__(self, myattr):
         self.myattr = myattr
@@ -233,7 +234,7 @@ class MethodDecoratorTests(TestCase):
 
         # t = Test()
         self.assertEqual(Test().method(), False)
-        
+
 
 class XFrameOptionsDecoratorsTests(TestCase):
     """

tests/migrations/test_checks.py

 # encoding: utf8
 from django.core import checks
 from django.core.checks.migrations import check_migrations
-from django.test import TestCase, override_settings
+from django.test import override_settings
 
 from .test_base import MigrationTestBase
 

tests/migrations/test_operations.py

@@ -478,6 +478,7 @@ class OperationTests(MigrationTestBase):
         """
 
         project_state = self.set_up_test_model("test_runpython")
+
         # Create the operation
         def inner_method(models, schema_editor):
             Pony = models.get_model("test_runpython", "Pony")