the default locations for cafile and capath.

encoding now always contains an encoding name.

encoding now always contains an encoding name.

changing IOError to OSError (#16715).

Thanks to Vajrasky Kok for the patch

test_imp.

to importlib.

Closes #11959: SMTPServer and SMTPChannel now take an optional map, use of which avoids affecting global state.

Fix bug in existing human test and add instructions; fix two bugs in tested
code; remove redundancies, add spaces, and change two internal method names.
Add mock_tk with mocks for tkinter.Variable subclasses and tkinter.messagebox.
Use mocks in test_config_name to unittest methods that are otherwise gui-free.

PEP accepted: http://mail.python.org/pipermail/python-dev/2013-June/126734.html

Cleanup also the code to follow the Python coding style (PEP 7).