def METHOD_NAME(client):
    max_date = deserialize_datetime("9999-12-31T23:59:59.999Z")
    dt = deserialize_iso(client.datetime.get_utc_lowercase_max_date_time())
    assert dt ==  max_date
    dt = deserialize_iso(client.datetime.get_utc_uppercase_max_date_time())
    assert dt ==  max_date
    client.datetime.put_utc_max_date_time(serialize_iso(max_date))