code: def neighbors(self, obj):
          
          neighbors = set([])
          
          for e in self.node_links[obj]:
              neighbors.update(set(self.edge_links[e]))
          
          return list(neighbors - set([obj]))
docs: Return all neighbors adjacent to the given node.
          
          @type  obj: node
          @param obj: Object identifier.
          
          @rtype:  list
          @return: List of all node objects adjacent to the given node.