old_contents: ct.models.Analysis = Backbone.Model.extend({
      id: null,
      name: null,
      loadDataArgs: null
  });
  
new_contents: ct.models.Analysis = Backbone.Model.extend({
      id: null,
      name: null,
      loadDataArgs: null,
  
      validate : function(attrs, options) {
          if (attrs.loadDataArgs === null) {
              return 'Load data not specified';
          }
      }
  });
  
subject: Add validation method for analysis model