def METHOD_NAME():
    hs = HourInterval(start_hour="07:20", stop_hour=None, freq="day")
    assert hs.start_hour == "07:20"
    assert hs.stop_hour.is_missing
    assert hs.period.freq == "day"
    expr = hs.filter_timestamp_column(EventsCallsTable.datetime)
    expected = "to_char(events.calls.datetime, 'HH24:MI') >= '07:20'"
    assert expected == get_string_representation(expr)