def _check_mods(A, B, AB, S):
    """Check the 'same' graph for differences in attributes """
    for nid, attrs in S.get_nodes().iteritems():
        if attrs != A.get_node(nid) or attrs != B.get_node(nid):
            AB.set_node_attribute(nid, 'diffstatus', 'modified')
    for eid, attrs in S.get_edges().iteritems():
        if attrs != A.get_edge(eid) or attrs != B.get_edge(eid):
            AB.set_edge_attribute(eid, 'diffstatus', 'modified')
