-int seat_node_enumerator(sd_bus *bus, const char *path, char ***nodes, void *userdata);
-int seat_object_find(sd_bus *bus, const char *path, const char *interface, void **found, void *seatdata);
+int seat_node_enumerator(sd_bus *bus, const char *path, void *userdata, char ***nodes, sd_bus_error *error);
+int seat_object_find(sd_bus *bus, const char *path, const char *interface, void *userdata, void **found, sd_bus_error *error);