code: def open(self):
          
          if self._state != 'open':
              if self._line is not None:
                  self._state = 'open'
                  self._nodes = self.grid.graph.nodes_from_line(self._line)
                  self.grid.graph.remove_edge(
                      self._nodes[0], self._nodes[1])
              else:
                  raise ValueError('``line`` is not set')
docs: Toggle state to open switch disconnector