Add six to required packages.

szymonlipinski · szymonlipinski · commit 5e603e5c25e2 · 2021-03-16T16:42:01.000+01:00
diff --git a/setup.py b/setup.py
@@ -38,6 +38,7 @@
     ),
     python_requires='>=2.7',
     install_requires=[
+        'six',
     ],
     extras_require={
         'testing': [
