def METHOD_NAME(graph):
    op = MockOpLastDirty(graph=graph)
    assert op._pending_dirty_mod_time == -1
    assert op._previous_dirty_mod_time == 13
    op.Input.setDirty((), _mod_time=42)
    assert op._pending_dirty_mod_time == -1
    assert op._previous_dirty_mod_time == 42