static void storeSessionData(const QString &key, const QVariant &data);
static QVariant retrieveSessionData(const QString &key, const QVariant &def = QVariant());
static QStringList sessionDataKeys();
static void storeSessionData(const QString &key, const QVariant &data);
static QVariant retrieveSessionData(const QString &key, const QVariant &def = QVariant());
static QStringList sessionDataKeys();