Class GridValidation

 // Add a grid item to a form and require one response per column. 
 const 
  
 form 
  
 = 
  
 FormApp 
 . 
 create 
 ( 
 'My Form' 
 ); 
 const 
  
 gridItem 
  
 = 
  
 form 
 . 
 addGridItem 
 (); 
 gridItem 
 . 
 setTitle 
 ( 
 'Rate your interests' 
 ) 
  
 . 
 setRows 
 ([ 
 'Cars' 
 , 
  
 'Computers' 
 , 
  
 'Celebrities' 
 ]) 
  
 . 
 setColumns 
 ([ 
 'Boring' 
 , 
  
 'So-so' 
 , 
  
 'Interesting' 
 ]); 
 const 
  
 gridValidation 
  
 = 
  
 FormApp 
 . 
 createGridValidation 
 () 
  
 . 
 setHelpText 
 ( 
 'Select one item per column.' 
 ) 
  
 . 
 requireLimitOneResponsePerColumn 
 () 
  
 . 
 build 
 (); 
 gridItem 
 . 
 setValidation 
 ( 
 gridValidation 
 );