Description: Up_six_PY
--- a/patsy/compat.py
+++ b/patsy/compat.py
@@ -48,3 +48,11 @@
             if isinstance(e, PatsyError):
                 e.set_origin(origin)
             raise
+
+# six
+import six
+if not hasattr(six, 'PY2'):
+    import sys
+    # Useful for very coarse version differentiation.
+    six.PY2 = sys.version_info[0] == 2
+    six.PY3 = sys.version_info[0] == 3
--- a/patsy/test_build.py
+++ b/patsy/test_build.py
@@ -9,7 +9,6 @@
 
 from __future__ import print_function
 
-import six
 import numpy as np
 import pytest
 from patsy import PatsyError
@@ -20,6 +19,7 @@
 from patsy.categorical import C
 from patsy.user_util import balanced, LookupFactor
 from patsy.design_info import DesignMatrix, DesignInfo
+from patsy.compat import six
 
 if have_pandas:
     import pandas
