Class DatePicker

const dateTimePicker =
    CardService.newDatePicker()
        .setTitle('Enter the date.')
        .setFieldName('date_field')
        // Set default value as Jan 1, 2018 UTC. Either a number or string is
        // acceptable.
        .setValueInMsSinceEpoch(1514775600)
        .setOnChangeAction(
            CardService.newAction().setFunctionName('handleDateTimeChange'),
        );