old_contents: export default {
  	extent: 3,
  	cells: [
  		[{ 
  			label: '2-', 
  			walls: { top: true, right: false, down: true, left: true },
  			values: []
  		 }, {
  			walls: { top: true, right: true, down: true, left: false },
  			values: []
  		 }, {
  			label: '2',
  			walls: { top: true, right: true, down: true, left: true }
  		 }],
  		[{
  			label: '2\u00F7',
  			walls: { top: true, right: true, down: false, left: true },
  			values: []
  		}, {
  			label: '3\u00F7',
  			walls: { top: true, right: false, down: true, left: true },
  			values: []
  		}, {
  			walls: { top: true, right: true, down: true, left: false },
  			values: []
  		}],
  		[{
  			walls: { top: false, right: true, down: true, left: true },
  			values: []
  		}, {
  			label: '1-',
  			walls: { top: true, right: false, down: true, left: true },
  			values: []
  		}, {
  			walls: { top: true, right: true, down: true, left: false },
  			values: []
  		}]
  	]
  }
  
new_contents: export default {
  	extent: 3,
  	cells: [
  		[{ 
  			label: '2-', 
  			walls: { top: true, right: false, down: true, left: true },
  			values: []
  		 }, {
  			walls: { top: true, right: true, down: true, left: false },
  			values: []
  		 }, {
  			label: '2',
  			walls: { top: true, right: true, down: true, left: true }
  			values: []
  		 }],
  		[{
  			label: '2\u00F7',
  			walls: { top: true, right: true, down: false, left: true },
  			values: []
  		}, {
  			label: '3\u00F7',
  			walls: { top: true, right: false, down: true, left: true },
  			values: []
  		}, {
  			walls: { top: true, right: true, down: true, left: false },
  			values: []
  		}],
  		[{
  			walls: { top: false, right: true, down: true, left: true },
  			values: []
  		}, {
  			label: '1-',
  			walls: { top: true, right: false, down: true, left: true },
  			values: []
  		}, {
  			walls: { top: true, right: true, down: true, left: false },
  			values: []
  		}]
  	]
  }
  
subject: Add missing values property