diff --git a/pybricks/util_mp/pb_kwarg_helper.h b/pybricks/util_mp/pb_kwarg_helper.h
index 67447e29d..9de0ed3d7 100644
--- a/pybricks/util_mp/pb_kwarg_helper.h
+++ b/pybricks/util_mp/pb_kwarg_helper.h
@@ -101,4 +101,7 @@
 // Optional keyword argument with default None value
 #define PB_ARG_DEFAULT_NONE(name)(name, MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE})
 
+// Test if all parsed arguments are None.
+#define PB_PARSE_ARGS_METHOD_ALL_NONE() (pb_obj_parsed_args_all_none(parsed_args, MP_ARRAY_SIZE(parsed_args)))
+
 #endif // PYBRICKS_INCLUDED_PBKWARG_H
diff --git a/pybricks/util_mp/pb_obj_helper.c b/pybricks/util_mp/pb_obj_helper.c
index c574c2e7b..f5ad41e3f 100644
--- a/pybricks/util_mp/pb_obj_helper.c
+++ b/pybricks/util_mp/pb_obj_helper.c
@@ -244,3 +244,18 @@ mp_obj_t pb_function_import_helper(qstr module_name, qstr function_name) {
     }
     return dest[0];
 }
+
+/**
+ * Tests that all parsed arguments are None.
+ *
+ * @param parsed_args     [in]  The parsed arguments.
+ * @param num_parsed_args [in]  The number of parsed arguments.
+ */
+bool pb_obj_parsed_args_all_none(mp_arg_val_t *parsed_args, size_t num_parsed_args) {
+    for (size_t i = 0; i < num_parsed_args; i++) {
+        if (parsed_args[i].u_obj != mp_const_none) {
+            return false;
+        }
+    }
+    return true;
+}
diff --git a/pybricks/util_mp/pb_obj_helper.h b/pybricks/util_mp/pb_obj_helper.h
index 940fc4fb1..339e72286 100644
--- a/pybricks/util_mp/pb_obj_helper.h
+++ b/pybricks/util_mp/pb_obj_helper.h
@@ -10,6 +10,7 @@
 #include <pbio/color.h>
 
 #include "py/obj.h"
+#include "py/runtime.h"
 
 // like mp_obj_get_int() but also allows float
 #if MICROPY_PY_BUILTINS_FLOAT
@@ -68,4 +69,6 @@ void pb_attribute_handler(mp_obj_t self_in, qstr attr, mp_obj_t *dest);
 
 mp_obj_t pb_function_import_helper(qstr module_name, qstr function_name);
 
+bool pb_obj_parsed_args_all_none(mp_arg_val_t *parsed_args, size_t num_parsed_args);
+
 #endif // PYBRICKS_INCLUDED_PBOBJ_H