Python 3.6 - DeprecationWarning: invalid escape sequence

[wesleybowman]

When running pytest, I see the following:

pyseeyou/grammar.py:34
  github/pyseeyou/pyseeyou/grammar.py:34: DeprecationWarning: invalid escape sequence \w
    ''')

<unknown>:1
  <unknown>:1: DeprecationWarning: invalid escape sequence \w
  <unknown>:1: DeprecationWarning: invalid escape sequence \w
  <unknown>:1: DeprecationWarning: invalid escape sequence \w
  <unknown>:1: DeprecationWarning: invalid escape sequence \.
  <unknown>:1: DeprecationWarning: invalid escape sequence \s

This warning came about because of https://bugs.python.org/issue27364