def display(self):
        """Display adjacency list.

        >>> g=Graph()
        >>> g.add(range(2), range(3))
        >>> g.display()
        0: {0, 1, 2}
        1: {0, 1, 2}
        2: {}
        """
        if _DEBUG: self._validate()
        for vid, v in self.iteritems():
            print "%s: %s" % (vid, v)
Display adjacency list.

        >>> g=Graph()
        >>> g.add(range(2), range(3))
        >>> g.display()
        0: {0, 1, 2}
        1: {0, 1, 2}
        2: {}
        
recipes/Python/578615_graph/recipe-578615.py