Class CheckboxGridValidationBuilder

CheckboxGridValidationBuilder is used to create validation rules for Checkbox Grid items in Google Forms.
The requireLimitOneResponsePerColumn() method is used to ensure that users select only one response per column in a Checkbox Grid item.
The example demonstrates how to add a Checkbox Grid item to a form and apply validation to limit responses per column.

A DataValidationBuilder for a CheckboxGridValidation.

// Add a checkbox grid item to a form and restrict it to one response per
// column.
const form = FormApp.openById('123abc');
const checkboxGridItem = form.addCheckboxGridItem();
checkboxGridItem.setTitle('Where did you celebrate New Years?')
    .setRows(['New York', 'San Francisco', 'London'])
    .setColumns(['2014', '2015', '2016', '2017']);
const checkboxGridValidation = FormApp.createcheckboxGridValidation()
                                   .setHelpText('Select one item per column.')
                                   .requireLimitOneResponsePerColumn()
                                   .build();
checkboxGridItem.setValidation(checkboxGridValidation);

Class CheckboxGridValidationBuilder

Detailed documentation

`requireLimitOneResponsePerColumn()`