code: function(idx, value) {
  
          idx = idx || 0;
          
          var labels = this.get('labels') || [];
          
          // Is it a getter?
          if (arguments.length === 0 || arguments.length === 1) {
              
              return labels[idx];
          }
  
          var newValue = _.merge({}, labels[idx], value);
  
          var newLabels = labels.slice();
          newLabels[idx] = newValue;
          
          return this.set({ labels: newLabels });
      }
docs: A convenient way to set labels. Currently set values will be mixined with `value` if used as a setter.