code: def _extract_prop_set(line):
      
      token = ' = "'
      line = line[4:]
      pos = line.find(token)
      return line[:pos], line[pos + 4:-1]
docs: Extract the (key, value)-tuple from a string like:
      >>> 'set foo = "bar"'
      :param line:
      :return: tuple (key, value)