docs: function (layers) {
  		var layersArray = this._toArray(layers),
  		    separated = this._checkInGetSeparated(layersArray),
  		    groups = separated.groups,
  		    i, group, id;
  
  		// Batch add all single layers.
  		this._originalAddLayers(separated.singles);
  
  		// Add Layer Groups to the map so that they are registered there and
  		// the map fires 'layeradd' events for them as well.
  		for (i = 0; i < groups.length; i++) {
  			group = groups[i];
  			id = L.stamp(group);
  			this._proxyLayerGroups[id] = group;
  			delete this._proxyLayerGroupsNeedRemoving[id];
  			if (this._map) {
  				this._map._originalAddLayer(group);
  			}
  		}
  	}