Fix the test; solution found by Christian Heimes.  Thanks!
diff --git a/Lib/test/test_pep263.py b/Lib/test/test_pep263.py
index ae61af9..dd13558 100644
--- a/Lib/test/test_pep263.py
+++ b/Lib/test/test_pep263.py
@@ -9,11 +9,11 @@
     def test_pep263(self):

         self.assertEqual(

             "ðÉÔÏÎ".encode("utf-8"),

-            '\xd0\x9f\xd0\xb8\xd1\x82\xd0\xbe\xd0\xbd'

+            b'\xd0\x9f\xd0\xb8\xd1\x82\xd0\xbe\xd0\xbd'

         )

         self.assertEqual(

             "\ð".encode("utf-8"),

-            '\\\xd0\x9f'

+            b'\\\xd0\x9f'

         )

 

 def test_main():