Fix linting issues

flake8/formatting/base.py

@@ -86,6 +86,7 @@ class BaseFormatter(object):
                                   ' format.')
 
     def show_benchmarks(self, benchmarks):
+        """Format and print the benchmarks."""
         pass
 
     def show_source(self, error):

tests/unit/test_base_formatter.py

@@ -1,11 +1,12 @@
 """Tests for the BaseFormatter object."""
 import optparse
 
-import mock
-import pytest
-
-from flake8.formatting import base
 from flake8 import style_guide
+from flake8.formatting import base
+
+import mock
+
+import pytest
 
 
 def options(**kwargs):