Added a test of the md5.hexdigest() method.  Funny enough, this test had yet-another Python implementation of a binary-data-to-hex-digit encoder!
Added a test of the md5.hexdigest() method.  Funny enough, this test
had yet-another Python implementation of a binary-data-to-hex-digit
encoder!

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