The documentation doesn't indicate that the Logger.exception method can accept kwargs like the other logging methods (Logger.debug, Logger.info, etc...) such as exc_info, stack_info, and extra.

https://docs.python.org/2.7/library/logging.html#logging.Logger.exception

The method signature is documented as: 

Logger.exception(msg, *args)

It should be:

Logger.exception(msg, *args, **kwargs)

It appears that this functionality was added in between Python 2.7.3 and 2.7.4 (http://bugs.python.org/issue15541) but that the documentation was never changed for the newer versions.