code: def to_graphviz(self) -> str:
          
          graph = "digraph finite_state_machine { rankdir=LR; node [fixedsize=true];"
          for origin, dest in self._transitions.items():
              origin = origin.replace(" ", "_")
              for d in dest:
                  d = d.replace(" ", "_")
                  graph += "{0} -> {1};".format(origin, d)
          graph += "}"
          return graph
docs: Converts the FSM behaviour structure to Graphviz syntax
  
          Returns:
            str: the graph in Graphviz syntax