Fix refcount bug in make_Zreplacement().
diff --git a/Modules/datetimemodule.c b/Modules/datetimemodule.c
index 61bba86..d220b56 100644
--- a/Modules/datetimemodule.c
+++ b/Modules/datetimemodule.c
@@ -1159,6 +1159,7 @@
 						Zreplacement, NULL);
 				if (Zreplacement == NULL)
 					return NULL;
+                                Py_INCREF(Zreplacement);
 			}
 			if (!PyString_Check(Zreplacement)) {
 				PyErr_SetString(PyExc_TypeError,