diff --git a/Objects/bytesobject.c b/Objects/bytesobject.c
index e6ab440..db93f37 100644
--- a/Objects/bytesobject.c
+++ b/Objects/bytesobject.c
@@ -896,6 +896,7 @@
     register unsigned char *p;
     register long x;
 
+    assert(_Py_HashSecret_Initialized);
     if (a->ob_shash != -1)
         return a->ob_shash;
     len = Py_SIZE(a);