code: def parse_dot_data(s):
      
      global top_graphs
      top_graphs = list()
      try:
          graphparser = graph_definition()
          graphparser.parseWithTabs()
          tokens = graphparser.parseString(s)
          return list(tokens)
      except ParseException as err:
          print(
              err.line +
              " "*(err.column-1) + "^" +
              err)
          return None
docs: Parse DOT description in (unicode) string `s`.
  
      @return: Graphs that result from parsing.
      @rtype: `list` of `pydot.Dot`