Added minor clarification in logging HOWTO.

Doc/howto/logging.rst

@@ -122,7 +122,8 @@ Logging to a file
 ^^^^^^^^^^^^^^^^^
 
 A very common situation is that of recording logging events in a file, so let's
-look at that next::
+look at that next. Be sure to try the following in a newly-started Python
+interpreter, and don't just continue from the session described above::
 
    import logging
    logging.basicConfig(filename='example.log',level=logging.DEBUG)