g_object_set: assertion 'G_IS_OBJECT (object)' failed g_object_set: assertion 'G_IS_OBJECT (object)' failed g_object_set: assertion 'G_IS_OBJECT (object)' failed g_object_set: assertion 'G_IS_OBJECT (object)' failed g_object_set: assertion 'G_IS_OBJECT (object)' failed g_object_set: assertion 'G_IS_OBJECT (object)' failed