Issue #16847: Fixed improper use of _PyUnicode_CheckConsistency() in

non-pydebug builds. Several extension modules now compile cleanly when
assert()s are enabled in standard builds (-DDEBUG flag).

Modules/sha256module.c

@@ -466,7 +466,9 @@ SHA256_hexdigest(SHAobject *self, PyObject *unused)
         c = (digest[i] & 0xf);
         hex_digest[j++] = Py_hexdigits[c];
     }
+#ifdef Py_DEBUG
     assert(_PyUnicode_CheckConsistency(retval, 1));
+#endif
     return retval;
 }