def get_edge_data(self, u, v, key=None, default=None):
        """Return the attribute dictionary associated with edge (u,v).

        Parameters
        ----------
        u, v : nodes

        default :  any Python object (default=None)
            Value to return if the edge (u,v) is not found.

        key : hashable identifier, optional (default=None)
            Return data only for the edge with specified key.

        Returns
        -------
        edge_dict : dictionary
            The edge attribute dictionary.

        Notes
        -----
        It is faster to use G[u][v][key].

        >>> G = nx.MultiGraph() # or MultiDiGraph
        >>> G.add_edge(0,1,key='a',weight=7)
        >>> G[0][1]['a']  # key='a'
        {'weight': 7}

        Warning: Assigning G[u][v][key] corrupts the graph data structure.
        But it is safe to assign attributes to that dictionary,

        >>> G[0][1]['a']['weight'] = 10
        >>> G[0][1]['a']['weight']
        10
        >>> G[1][0]['a']['weight']
        10

        Examples
        --------
        >>> G = nx.MultiGraph() # or MultiDiGraph
        >>> nx.add_path(G, [0, 1, 2, 3])
        >>> G.get_edge_data(0,1)
        {0: {}}
        >>> e = (0,1)
        >>> G.get_edge_data(*e) # tuple form
        {0: {}}
        >>> G.get_edge_data('a','b',default=0) # edge not in graph, return 0
        0
        """
        try:
            if key is None:
                return self.adj[u][v]
            else:
                return self.adj[u][v][key]
        except __HOLE__:
            return default
dataset/ETHPy150Open networkx/networkx/networkx/classes/multigraph.py/MultiGraph.get_edge_data