diff --git a/Doc/library/unittest.rst b/Doc/library/unittest.rst
index bdecb3a..4c39b82 100644
--- a/Doc/library/unittest.rst
+++ b/Doc/library/unittest.rst
@@ -1674,7 +1674,7 @@
 
    .. method:: addError(test, err)
 
-      Called when the test case *test* raises an unexpected exception *err* is a
+      Called when the test case *test* raises an unexpected exception. *err* is a
       tuple of the form returned by :func:`sys.exc_info`: ``(type, value,
       traceback)``.