py23 import in all nontrivial source files and unused import cleanup
diff --git a/Lib/fontTools/pens/cocoaPen.py b/Lib/fontTools/pens/cocoaPen.py
index 67482b4..88d8e96 100644
--- a/Lib/fontTools/pens/cocoaPen.py
+++ b/Lib/fontTools/pens/cocoaPen.py
@@ -1,4 +1,5 @@
 from fontTools.pens.basePen import BasePen
+from fontTools.misc.py23 import *
 
 
 __all__ = ["CocoaPen"]