diff --git a/Lib/unittest/case.py b/Lib/unittest/case.py
index ed17b6e..4f9c496 100644
--- a/Lib/unittest/case.py
+++ b/Lib/unittest/case.py
@@ -117,8 +117,7 @@
             # let unexpected exceptions pass through
             return False
         #store exception, without traceback, for later retrieval
-        self.exc_value = exc_value
-        self.exc_value.with_traceback(None)
+        self.exc_value = exc_value.with_traceback(None)
         if self.expected_regex is None:
             return True