fix circula deps of six - lint fix

setup.py

@@ -6,7 +6,6 @@ import shutil
 import sys
 from importlib import import_module
 
-import six
 from setuptools import Extension, setup
 from setuptools.command.install import install
 
@@ -83,7 +82,7 @@ if __name__ == "__main__":
         'images/kivy/text_images*.png'
     ]}
 
-    if six.PY3:
+    if sys.version_info[0] == 3:
         packages.extend(
             [
                 'pybitmessage.bitmessagekivy',
@@ -92,7 +91,9 @@ if __name__ == "__main__":
         )
 
     if os.environ.get('INSTALL_TESTS', False):
-        packages.extend(['pybitmessage.mockbm', 'pybitmessage.backend', 'pybitmessage.bitmessagekivy.tests'])
+        packages.extend(
+            ['pybitmessage.mockbm', 'pybitmessage.backend', 'pybitmessage.bitmessagekivy.tests']
+        )
         package_data[''].extend(['bitmessagekivy/tests/sampleData/*.dat'])
 
     # this will silently accept alternative providers of msgpack