How to connect a signal with dbus signature 'a{sv}'?

[Mozzie]

Hi,
I am using QtDBus, I can connect dbus signal with base C++ types such as int, boolean, but one day I meet a signal who's signature is 'a{sv}', first I think it might be QVariantMap but it did not work, and I found a document mentioned about this, QVariantMap .
so which type should be when the argument signature is 'a{sv}'?

Thank you.