diff --git a/rattail/gpc.py b/rattail/gpc.py
index b6da852e352b58f7fe19f475e3fa1a6184ee1c05..748cefda35d9d3ee0e1831bd4fc51c8da844e856 100644
--- a/rattail/gpc.py
+++ b/rattail/gpc.py
@@ -2,7 +2,7 @@
 ################################################################################
 #
 #  Rattail -- Retail Software Framework
-#  Copyright © 2010-2014 Lance Edgar
+#  Copyright © 2010-2016 Lance Edgar
 #
 #  This file is part of Rattail.
 #
@@ -24,7 +24,7 @@
 Global Product Code
 """
 
-from __future__ import unicode_literals
+from __future__ import unicode_literals, absolute_import
 
 from rattail import barcodes
 
@@ -74,13 +74,20 @@ class GPC(object):
             return True
 
     def __cmp__(self, other):
-        if int(self) < int(other):
+
+        # treat non-integers as being less than myself
+        try:
+            other = int(other)
+        except (TypeError, ValueError):
+            return 1
+
+        myself = int(self)
+        if myself < other:
             return -1
-        if int(self) > int(other):
+        if myself > other:
             return 1
-        if int(self) == int(other):
-            return 0
-        assert False
+        assert myself == other
+        return 0
 
     def __hash__(self):
         return hash(self.value)