Class CheckboxValidationBuilder

// Add a checkBox item to a form and require exactly two selections. const form = FormApp.create('My Form'); const checkBoxItem = form.addCheckboxItem(); checkBoxItem.setTitle('What two condiments would you like on your hot dog?'); checkBoxItem.setChoices([  checkBoxItem.createChoice('Ketchup'),  checkBoxItem.createChoice('Mustard'),  checkBoxItem.createChoice('Relish'), ]); const checkBoxValidation = FormApp.createCheckboxValidation()  .setHelpText('Select two condiments.')  .requireSelectExactly(2)  .build(); checkBoxItem.setValidation(checkBoxValidation);