//HOW TO CALL VARIANT?:
        else if (!dbus_message_iter_open_container(&arguments_iterator, DBUS_TYPE_VARIANT, DBUS_TYPE_DOUBLE_AS_STRING, &subIter)) {
            ::dbus_message_unref(dbus_msg);
            throw Error("Error", "Failed to allocate memory");
        }
        else if (!dbus_message_iter_append_basic(&subIter, DBUS_TYPE_DOUBLE, &volume)) {
            ::dbus_message_unref(dbus_msg);
            throw Error("Error", "Failed to allocate memory");
        }
        else if (!dbus_message_iter_close_container(&arguments_iterator, &subIter)) {
            ::dbus_message_unref(dbus_msg);
            throw Error("Error", "Failed to allocate memory");
        }