def METHOD_NAME():
    # these are hard coded from what was generated by date_to_sec
    # they cross the spring transition, and caused a problem.
    seconds = np.array([1457857800, 1457859600, 1457861400,
                        1457863200, 1457865000, 1457866800],
                       dtype=np.uint32)
    dates = sec_to_date(seconds)
    diff = np.diff(dates).astype(np.int64)
    # checks that the interval is constant -- i.e. no repeated or skipped times
    assert not np.any(np.diff(diff))