Minor clean up according to flake8.

sqlalchemy_utils/__init__.py

@@ -6,6 +6,7 @@ from .functions import (
     primary_keys,
     render_statement,
     render_expression,
+    create_mock_engine,
     mock_engine,
     sort_query,
     table_name,
@@ -53,6 +54,9 @@ __all__ = (
     primary_keys,
     proxy_dict,
     render_statement,
+    render_expression,
+    create_mock_engine,
+    mock_engine,
     sort_query,
     table_name,
     with_backrefs,

sqlalchemy_utils/functions/__init__.py

@@ -7,7 +7,6 @@ import inspect
 import sqlalchemy as sa
 from sqlalchemy.orm.query import Query
 from sqlalchemy.schema import MetaData, Table, ForeignKeyConstraint
-from sqlalchemy.engine import url
 from six.moves import cStringIO
 from .batch_fetch import batch_fetch, with_backrefs, CompositePath
 from .defer_except import defer_except
@@ -323,7 +322,7 @@ def mock_engine(engine, stream=None):
 
     # Evaluate the expression and get the target engine.
 
-    frame.f_locals['__mock'] = mock = create_mock_engine(target, stream)
+    frame.f_locals['__mock'] = create_mock_engine(target, stream)
 
     # Replace the target with our mock.
 

tests/test_utility_functions.py

@@ -2,7 +2,6 @@ import sqlalchemy as sa
 from sqlalchemy_utils import escape_like
 from sqlalchemy_utils.functions import naturally_equivalent
 from tests import TestCase
-from six.moves import cStringIO
 from sqlalchemy_utils.functions import (
     non_indexed_foreign_keys,
     render_statement,