diff --git a/Python/instrumentation.c b/Python/instrumentation.c
index 13bdd041becd69..5b26a078085806 100644
--- a/Python/instrumentation.c
+++ b/Python/instrumentation.c
@@ -2558,18 +2558,22 @@ PyObject *_Py_CreateMonitoringObject(void)
     err = PyObject_SetAttrString(events, "NO_EVENTS", _PyLong_GetZero());
     if (err) goto error;
     PyObject *val = PyLong_FromLong(PY_MONITORING_DEBUGGER_ID);
+    assert(val != NULL); /* Can't return NULL because the int is small. */
     err = PyObject_SetAttrString(mod, "DEBUGGER_ID", val);
     Py_DECREF(val);
     if (err) goto error;
     val = PyLong_FromLong(PY_MONITORING_COVERAGE_ID);
+    assert(val != NULL);
     err = PyObject_SetAttrString(mod, "COVERAGE_ID", val);
     Py_DECREF(val);
     if (err) goto error;
     val = PyLong_FromLong(PY_MONITORING_PROFILER_ID);
+    assert(val != NULL);
     err = PyObject_SetAttrString(mod, "PROFILER_ID", val);
     Py_DECREF(val);
     if (err) goto error;
     val = PyLong_FromLong(PY_MONITORING_OPTIMIZER_ID);
+    assert(val != NULL);
     err = PyObject_SetAttrString(mod, "OPTIMIZER_ID", val);
     Py_DECREF(val);
     if (err) goto error;