def _to_bel_lines_footer(graph) -> Iterable[str]:
    """Iterate the lines of a BEL graph's corresponding BEL script's footer.

    :param pybel.BELGraph graph: A BEL graph
    """
    unqualified_edges_to_serialize = [
        (u, v, d)
        for u, v, d in graph.edges(data=True)
        if d[RELATION] in UNQUALIFIED_EDGES and EVIDENCE not in d
    ]

    isolated_nodes_to_serialize = [
        node
        for node in graph
        if not graph.pred[node] and not graph.succ[node]
    ]

    if unqualified_edges_to_serialize or isolated_nodes_to_serialize:
        yield '###############################################\n'
        yield 'SET Citation = {"PubMed","Added by PyBEL","29048466"}'
        yield 'SET SupportingText = "{}"'.format(PYBEL_AUTOEVIDENCE)

        for u, v, data in unqualified_edges_to_serialize:
            yield '{} {} {}'.format(u.as_bel(), data[RELATION], v.as_bel())

        for node in isolated_nodes_to_serialize:
            yield node.as_bel()

        yield 'UNSET SupportingText'
        yield 'UNSET Citation'
Iterate the lines of a BEL graph's corresponding BEL script's footer.

    :param pybel.BELGraph graph: A BEL graph