diff --git a/Doc/c-api/intro.rst b/Doc/c-api/intro.rst
index c3a9ed6..6414277 100644
--- a/Doc/c-api/intro.rst
+++ b/Doc/c-api/intro.rst
@@ -255,8 +255,10 @@
            PyObject *index = PyInt_FromLong(i);
            if (!index)
                return -1;
-           if (PyObject_SetItem(target, index, item) < 0)
+           if (PyObject_SetItem(target, index, item) < 0) {
+               Py_DECREF(index);
                return -1;
+       }
            Py_DECREF(index);
        }
        return 0;