There is no TestError, use TestFailed appropriately
diff --git a/Lib/test/test_mpz.py b/Lib/test/test_mpz.py
index 3e0a700..2e57db4 100644
--- a/Lib/test/test_mpz.py
+++ b/Lib/test/test_mpz.py
@@ -1,6 +1,6 @@
 
 import mpz
-from test_support import vereq
+from test_support import vereq, TestFailed
 
 def check_conversion(num):
     mpz_num = mpz.mpz(num)