title: Reversing a regular expression in Python
body: <p>I want to reverse a regular expression. I.e. given a regular expression, I want to produce <em>any</em> string that will match that regex.</p>
  
  <p>I know how to do this from a theoretical computer science background using a finite state machine, but I just want to know if someone has already written a library to do this. :)</p>
  
  <p>I'm using Python, so I'd like a Python library.</p>
  
  <p>To reiterate, I only want <em>one</em> string that will match the regex. Things like "." or ".*" would make an infinite amount of strings match the regex, but I don't care about all options.</p>
  
  <p>I'm willing for this library to only work on a certain subset of regex.</p>