public function _deleteByWildcard( $wildcard, $fname = false )
    {
        if ( $fname )
            $fname .= "::_deleteByWildcard($wildcard)";
        else
            $fname = "_deleteByWildcard($wildcard)";
        return $this->_protect( array( $this, '_deleteByWildcardInner' ), $fname,
                                $wildcard, $fname );
    }