diff --git a/Objects/stringobject.c b/Objects/stringobject.c
index 0b6d36c..f95857a 100644
--- a/Objects/stringobject.c
+++ b/Objects/stringobject.c
@@ -1594,7 +1594,7 @@
     Py_ssize_t i;
     PyObject *seq, *item;
 
-    seq = PySequence_Fast(orig, "");
+    seq = PySequence_Fast(orig, "can only join an iterable");
     if (seq == NULL) {
         return NULL;
     }