objexcept: Add mp_obj_new_exception_arg1() convenience function.
diff --git a/py/objexcept.c b/py/objexcept.c
index 781a004..5b6c96b 100644
--- a/py/objexcept.c
+++ b/py/objexcept.c
@@ -191,6 +191,11 @@
     return mp_obj_new_exception_args(exc_type, 0, NULL);
 }
 
+// "Optimized" version for common(?) case of having 1 exception arg
+mp_obj_t mp_obj_new_exception_arg1(const mp_obj_type_t *exc_type, mp_obj_t arg) {
+    return mp_obj_new_exception_args(exc_type, 1, &arg);
+}
+
 mp_obj_t mp_obj_new_exception_args(const mp_obj_type_t *exc_type, uint n_args, const mp_obj_t *args) {
     assert(exc_type->make_new == mp_obj_exception_make_new);
     return exc_type->make_new((mp_obj_t)exc_type, n_args, 0, args);