def match_complex_metapath(graph, node, complex_metapath):
raise NotImplementedError<EOL>
Matches a complex metapath starting at the given node

    :param pybel.BELGraph graph: A BEL graph
    :param tuple node: A BEL node
    :param list[str] complex_metapath: An iterable of alternating BEL nodes and relations
    :return: An iterable over paths from the node matching the metapath
    :rtype: iter[tuple]