diff --git a/Python/getargs.c b/Python/getargs.c
index 600941d..0069671 100644
--- a/Python/getargs.c
+++ b/Python/getargs.c
@@ -1633,6 +1633,7 @@
     case 'z': /* string or None */
     case 'y': /* bytes */
     case 'u': /* unicode string */
+    case 'Z': /* unicode string or None */
     case 'w': /* buffer, read-write */
         {
             (void) va_arg(*p_va, char **);