def del_graph(self, name):
        """Remove all traces of a graph's existence from the database

        :arg name: name of an existing graph

        """
        # make sure the graph exists before deleting anything
        self.get_graph(name)
        self.query.del_graph(name)
        if name in self._graph_objs:
            del self._graph_objs[name]
Remove all traces of a graph's existence from the database

        :arg name: name of an existing graph