Python3: ModuleNotFoundError: No module named 'StringIO'

[Peter Suter]

Plugin fails to load with Python3:

	ModuleNotFoundError: No module named 'StringIO'

[Peter Suter]

cards/core.py

@@ -4 +4 @@
 from json.encoder import JSONEncoder
 import pkg_resources
 import re
-from StringIO import StringIO
+try:
+    from StringIO import StringIO # Python 2
+except ImportError:
+    from io import StringIO # Python 3
 
 from trac import __version__
 from trac.db.api import DatabaseManager

[Peter Suter]

In 17667:

CardsPlugin: Python3 compatibility.
(fix #13735)