static function &get_reference( $type, $id ) {
		if( empty( self::$stack[ $type ][ $id ] ) ){
			$null = null;
			return $null;
		}	
		else {
			return self::$stack[ $type ][ $id ];
		}
	}
static function &get_reference( $type, $id ) {
		if( empty( self::$stack[ $type ][ $id ] ) ){
			$null = null;
			return $null;
		}	
		else {
			return self::$stack[ $type ][ $id ];
		}
	}
static function & get_reference ( $ type , $ id ) { if ( empty ( self :: $ stack [ $ type ] [ $ id ] ) ) { $ null = null ; return $ null ; } else { return self :: $ stack [ $ type ] [ $ id ] ; } }
Get a reference to an error instance.
@internal
@param int
@param int
@return PLUGError
Get a reference to an error instance .