docs: function(scopeDefinition, attrs) {
          for (var i in scopeDefinition) {
            if (scopeDefinition.hasOwnProperty(i) && attrs[i] === void 0 &&
                attrs[scopeDefinition[i].substr(1, scopeDefinition[i].length)] === void 0) {
              delete scopeDefinition[i];
            }
          }
  
          return scopeDefinition;
        }