Add basic tests for the return value of os.popen().close(). According to #6358, python 3.0 has a different implementation that behaves differently.
Add basic tests for the return value of os.popen().close().
According to #6358, python 3.0 has a different implementation that behaves differently.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator