Merge pull request matplotlib#3357 from jenshnielsen/qt4_unicode

backend_qt5.py Don't use six.u

Author: tacaswell

lib/matplotlib/backends/backend_qt5.py

@@ -381,7 +381,7 @@ def _get_key(self, event):
                 key = key.lower()
 
         mods.reverse()
-        return six.u('+').join(mods + [key])
+        return '+'.join(mods + [key])
 
     def new_timer(self, *args, **kwargs):
         """