def prune_graph_nodes(graph, tag):
    """
    Filers graph nodes to only nodes that are tagged with the specified tag
    :param graph: Original graph to prune
    :param tag: Tag for nodes of interest
    :return: List of nodes tagged with the specified tag
    """
    node_list = []
    for node_name in graph.nodes():
        try:
            if graph.node[node_name]['tag'] == tag:
#            if graph.node[node_name]['attr_dict'][TAG_ATTR] == tag:
                node_list.append(node_name)
        except KeyError:
            pass
    return node_list