public function delete( $object ) {
		// do nothing if an object was generated not by this factory
		if ( ! in_array( $object, $this->_objects ) ) {
			return false;
		}

		// delete object and remove it from the objects list
		$deleted = $this->_deleteObject( $object );
		if ( $deleted && ! is_wp_error( $deleted ) ) {
			$index = array_search( $object, $this->_objects );
			if ( false !== $index ) {
				unset( $this->_objects[ $index ] );
			}
		}

		return $deleted;
	}