Use iteritems from the six module for Python 3 compatibility
diff --git a/tests/test_utils.py b/tests/test_utils.py
index 5223153..11bb919 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -16,6 +16,8 @@
 import os
 import textwrap
 
+import six
+
 import pretend
 
 import pytest
@@ -1888,7 +1890,7 @@
     expected = []
     for dictionary in expected_vectors:
         new_dict = {}
-        for k, v in dictionary.iteritems():
+        for k, v in six.iteritems(dictionary):
             v = v.strip()
             v = v.replace(" ", "")
             v = int(v, 16)