diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 9d11546..1068916 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -781,6 +781,7 @@
     _PyUnicode_LENGTH(unicode) = 0;
     _PyUnicode_UTF8(unicode) = NULL;
     _PyUnicode_UTF8_LENGTH(unicode) = 0;
+    assert(_PyUnicode_CheckConsistency(unicode, 0));
     return unicode;
 
   onError: