private function has($key) {
		return isset($_SESSION[self::SESSION_KEY_FLASH]) && isset($_SESSION[self::SESSION_KEY_FLASH][$key]);
	}
private function has($key) {
		return isset($_SESSION[self::SESSION_KEY_FLASH]) && isset($_SESSION[self::SESSION_KEY_FLASH][$key]);
	}
private function has ( $ key ) { return isset ( $ _SESSION [ self :: SESSION_KEY_FLASH ] ) && isset ( $ _SESSION [ self :: SESSION_KEY_FLASH ] [ $ key ] ) ; }
Returns whether a message of the specified type is available

@param string $key the type of the message (usually one of the constants in this class starting with `FLASH_KEY_`)
@return bool
Returns whether a message of the specified type is available