code: function(index, key, obj) {
          if (Ext.isIterable(key)) {
              return this.doInsert(index, key, obj);
          }
          return (obj ? this.doInsert(index, [key], [obj]) : this.doInsert(index, [key]))[0];
      }
docs: </deprecated> 
  Inserts an item at the specified index in the collection. Fires the {@link #event-add} event when complete.
  @param {Number} index The index to insert the item at.
  @param {String/Object/String[]/Object[]} key The key to associate with the new item, or the item itself.
  May also be an array of either to insert multiple items at once.
  @param {Object/Object[]} o (optional) If the second parameter was a key, the new item.
  May also be an array to insert multiple items at once.
  @return {Object} The item inserted or an array of items inserted.
  @since Ext 1