private function _error($message, $level = E_USER_NOTICE)
	{
		$caller = next(debug_backtrace());

		switch ($level)
		{
			case E_USER_NOTICE:
				echo "Notice: ";
				break;
			case E_USER_ERROR:
				echo "Fatal error: ";
				break;
			default:
				echo "Unknown error: ";
				break;
		}

		echo $message . ' in ' . $caller['file'] . ' on line ' . $caller['line'] . "\n";
	}