code: def comment_handle(self, original, loc, tokens):
          
          internal_assert(len(tokens) == 1, "invalid comment tokens", tokens)
          ln = self.adjust(lineno(loc, original))
          internal_assert(lambda: ln not in self.comments, "multiple comments on line", ln)
          self.comments[ln] = tokens[0]
          return ""
docs: Store comment in comments.