code: def graph_add_node(self, node_object):
          
          if ((node_object not in self._graph.nodes()) and
              (isinstance(node_object, (StationDing0,
                                        CableDistributorDing0,
                                        LVLoadAreaCentreDing0,
                                        CircuitBreakerDing0,
                                        GeneratorDing0)))):
              self._graph.add_node(node_object)
docs: Adds a station or cable distributor object to grid graph if not already existing
          
          Parameters
          ----------
          node_object : GridDing0
              Description #TODO