python3-zope.event 4.4-2build1 (amd64 binary) in ubuntu focal

 This package provides a simple event system. It provides an event publishing
 system and a very simple event-dispatching system on which more sophisticated
 event dispatching systems can be built. For example, a type-based event
 dispatching system that builds on zope.event can be found in zope.component.
 .
 This is the Python 3 library.