docs: function( evaluator, guard, boundary ) {
  			var walkerRange = this.clone();
  			walkerRange.collapse();
  			walkerRange.setEndAt( boundary || this.root, CKEDITOR.POSITION_BEFORE_END );
  
  			var walker = new CKEDITOR.dom.walker( walkerRange );
  			walker.evaluator = evaluator;
  			walker.guard = guard;
  			return walker.next();
  		}