Does Python have any kind of 'messaging'?

[j_mckitrick]

I used to like Objective-C and Gnustep, but I gave up for lack of
support and recognition of the language/platform under Unix.  But it
did offer NSNotifications, a basic message class that could be posted
and received by all subscribers.  Other than global variables used to
share data across threads, does Python have anything similar?

jonathon