docs: function( evaluator, guard, boundary ) {
  			var walkerRange = this.clone();
  			walkerRange.collapse( 1 );
  			walkerRange.setStartAt( boundary || this.root, CKEDITOR.POSITION_AFTER_START );
  
  			var walker = new CKEDITOR.dom.walker( walkerRange );
  			walker.evaluator = evaluator;
  			walker.guard = guard;
  			return walker.previous();
  		}