diff --git a/Lib/unittest/case.py b/Lib/unittest/case.py
index f99c4e5..225a143 100644
--- a/Lib/unittest/case.py
+++ b/Lib/unittest/case.py
@@ -130,7 +130,7 @@
         raise self.test_case.failureException(msg)
 
 def _sentinel(*args, **kwargs):
-    raise AssertionError('Should never called')
+    raise AssertionError('Should never be called')
 
 class _AssertRaisesBaseContext(_BaseTestCaseContext):