def METHOD_NAME():
    """
    flowmachine.utils.time_period_add does what it says on the tin.
    """
    assert time_period_add("2016-01-01", 3) == "2016-01-04 00:00:00"
    assert time_period_add("2017-12-31", 1) == "2018-01-01 00:00:00"