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);