docs: def lex(self, text):
          "Only lex (and postlex) the text, without parsing it. Only relevant when lexer='standard'"
          if not hasattr(self, 'lexer'):
              self.lexer = self._build_lexer()
          stream = self.lexer.lex(text)
          if self.options.postlex:
              return self.options.postlex.process(stream)
          return stream