Line 35 is "import sys" so sys imports within functions are superfluous, as well as contrary to current guidelines. There is another on 1033. Both were removed before 3.3, so this amounts to a 2.7 backport.

It took me a moment to see that the unneeded conditional import is not innocuous, as it localizes 'sys' while sometimes leaving it unbound. Good catch.

Yashuhiro, can you sign a PSF contributor license agreement? The electronic version is easy.
  http://www.python.org/psf/contrib/contrib-form/
We don't really need it for this patch, but we hope to see more from you.

A minimal test would be a unittest version of
  assert isinstance(Tk(baseName="test"), Tk)
This mainly tests that no exceptions are raised when the arg is present. The doc may suggest that baseName should have a visible effect on the instance that could be tested. If there is already a 3.x test, it should be backported. If not, anything added to 2.7 should be added to 3.x also.