title: Python error because of regex inside a Google Big Query
body: <p>I am writing Google Big Query wrappers in python. One of the queries has a regex and the python code is treating it as an syntax error.</p>
  
  <p>Here is the regex 
  WHEN tier2 CONTAINS '-' THEN REGEXP_EXTRACT(tier2,'(.*)\s-')</p>
  
  <p>the error is Invalid string literal: '(.*)\s-'>
  The error is for \ in the regex.
  Any suggestion to overcome it</p>