Adds edges to the graph. Takes optional arguments for 
        ``DictGraph.add_edge``.
        
        Arguments:
        
          - edges(iterable) Sequence of edges to be added to the 
            ``DictGraph``.

def add_edges(self, edges, *args, **kwargs):
        """
        Adds edges to the graph. Takes optional arguments for 
        ``DictGraph.add_edge``.
        
        Arguments:
        
          - edges(iterable) Sequence of edges to be added to the 
            ``DictGraph``.
          
        """
        for edge in edges:
            self.add_edge(edge, *args, **kwargs)