Python 3 publish-subcribe library

 Provides a publish-subscribe API to facilitate event-based or message-based
 architecture in a single-process application. It is pure Python
 and works on Python 3.3+. It is centered on the notion of a topic;
 senders publish messages of a given topic, and listeners subscribe to
 messages of a given topic, all inside the same process. The package also
 supports a variety of advanced features that facilitate debugging and
 maintaining topics and messages in larger desktop- or server-based
 applications.