Created originally on Bitbucket by jdufresne (Jon Dufresne)
Was already merged in Bitbucket before import, marked as merged by the import user
Starting Python 3.6, using a backslash that is not a valid escape sequence generates a deprecation warning. This will produce an error in a future Python version. For additional details, see the PYthon release notes:
https://docs.python.org/3/whatsnew/3.6.html#deprecated-python-behavior
A backslash-character pair that is not a valid escape sequence now generates a DeprecationWarning. Although this will eventually become a SyntaxError, that will not be for several Python releases.
Fixes warnings of the form
DeprecationWarning: invalid escape sequence .