code: def match(self, string):
          
          m = self._re.match(string)
  
          if m:
              return Match(string, [(self._re, m)], self._group_names_to_nodes, self.unescape_funcs)
docs: Match the string with the grammar.
          Returns a :class:`Match` instance or `None` when the input doesn't match the grammar.
  
          :param string: The input string.