code: def do_conneg(accept, supported):
      
      for result in parse_accept_header(accept):
          mime_type = result[0]
          if (mime_type in supported):
              return mime_type
      return None
docs: Parse accept header and look for preferred type in supported list.
  
      Arguments:
          accept - HTTP Accept header
          supported - list of MIME type supported by the server
  
      Returns:
          supported MIME type with highest q value in request, else None.
  
      FIXME - Should replace this with negotiator2