code: def graph_nodes_from_branch(self, branch):
          
          edges = nx.get_edge_attributes(self._graph, 'branch')
          nodes = list(edges.keys())[list(edges.values()).index(branch)]
          return nodes
docs: Returns nodes that are connected by `branch`
  
          Args
          ----
          branch: BranchDing0
              Description #TODO
                  
          Returns
          -------
          (:obj:`GridDing0`, :obj:`GridDing0`)
              2-tuple of nodes (Ding0 objects) #TODO:Check