diff --git a/simplejson/_speedups.c b/simplejson/_speedups.c
index 80c12cb773a26e1866dbe73e9545b1d52ab3b913_c2ltcGxlanNvbi9fc3BlZWR1cHMuYw==..6a3e1e8ea57d38b9a0b3f012ca21dd14467426d4_c2ltcGxlanNvbi9fc3BlZWR1cHMuYw== 100644
--- a/simplejson/_speedups.c
+++ b/simplejson/_speedups.c
@@ -2616,5 +2616,5 @@
     s->tuple_as_array = PyObject_IsTrue(tuple_as_array);
     s->bigint_as_string = PyObject_IsTrue(bigint_as_string);
     if (item_sort_key != Py_None) {
-        if (!PyCallable_Check(item_sort_key))
+        if (!PyCallable_Check(item_sort_key)) {
             PyErr_SetString(PyExc_TypeError, "item_sort_key must be None or callable");
@@ -2620,4 +2620,6 @@
             PyErr_SetString(PyExc_TypeError, "item_sort_key must be None or callable");
+	    return -1;
+	}
     }
     else if (PyObject_IsTrue(sort_keys)) {
         static PyObject *itemgetter0 = NULL;