diff -Nur jurko-suds-94664ddd46a6/tests/test_transport.py ../jurko-suds-94664ddd46a6/tests/test_transport.py
--- jurko-suds-94664ddd46a6/tests/test_transport.py	2015-07-27 17:08:20.000000000 +0800
+++ jurko-suds-94664ddd46a6/tests/test_transport.py	2020-06-24 17:34:24.760915206 +0800
@@ -140,7 +140,7 @@
         ("", {}, "\n\n\n\n\n\n"),
         ("", {}, u("\u4E2D\u539F\u5343\u519B\u9010\u848B"))))
     def test_string_representation_with_message(self, url, headers, message):
-        for key, value in headers.items():
+        for key, value in list(headers.items()):
             old_key = key
             if isinstance(key, text_type):
                 key = key.encode("utf-8")