Add six to required packages.

szymonlipinski · szymonlipinski · commit 9bda97bbaba3 · 2020-12-18T13:08:32.000+01:00
diff --git a/setup.py b/setup.py
@@ -33,6 +33,7 @@
     ),
     python_requires='>=2.7',
     install_requires=[
+        'six',
     ],
     extras_require={
         'testing': [
