code: def plot_dot_graph(graph, filename=None):
      
      if not plot.pygraphviz_available:
          logger.error("Pygraphviz is not installed, cannot generate graph plot!")
          return
      if not plot.PIL_available:
          logger.error("PIL is not installed, cannot display graph plot!")
          return
  
      agraph = AGraph(graph)
      agraph.layout(prog='dot')
      if filename is None:
          filename = tempfile.mktemp(suffix=".png")
      agraph.draw(filename)
      image = Image.open(filename)
      image.show()
docs: Plots a graph in graphviz dot notation.
  
      :param graph: the dot notation graph
      :type graph: str
      :param filename: the (optional) file to save the generated plot to. The extension determines the file format.
      :type filename: str