def __init__(self, init={}, VertexType=Vertex):
        """Create the graph, optionally initializing from another graph.
        Optional VertexType parameter can be passed to specify default vertex type.

        >>> g = Graph(VertexType=WVertex)
        >>> len(g), g
        (0, {})
        >>> g.add([1, 2, 3], [2, 3], 5)
        >>> print g
        {1: {2: 5, 3: 5}, 2: {2: 5, 3: 5}, 3: {2: 5, 3: 5}}
        >>> g2 = Graph(g, Vertex)       #can initialize with other Graph type, will convert to Vertex type
        >>> print g2
        {1: {2, 3}, 2: {2, 3}, 3: {2, 3}}
        """
        self.VertexType = VertexType
        super(Graph, self).__init__(init, {}, MERGE_VERTEX)
Create the graph, optionally initializing from another graph.
        Optional VertexType parameter can be passed to specify default vertex type.

        >>> g = Graph(VertexType=WVertex)
        >>> len(g), g
        (0, {})
        >>> g.add([1, 2, 3], [2, 3], 5)
        >>> print g
        {1: {2: 5, 3: 5}, 2: {2: 5, 3: 5}, 3: {2: 5, 3: 5}}
        >>> g2 = Graph(g, Vertex)       #can initialize with other Graph type, will convert to Vertex type
        >>> print g2
        {1: {2, 3}, 2: {2, 3}, 3: {2, 3}}
        
recipes/Python/578615_graph/recipe-578615.py