def METHOD_NAME(datetime_object, date_format, runtime):
    # https://learn.microsoft.com/en-us/javascript/api/requirement-sets/excel/custom-functions-requirement-sets
    serial = utils.datetime_to_xlserial(datetime_object)
    if float(runtime) < 1.4:
        return serial
    else:
        return {
            "type": "FormattedNumber",
            "basicValue": serial,
            "numberFormat": date_format,
        }