Random examples from the Web.
Example1:
http://hepmcvisual.hepforge.org/svn/HepMCBrowser/tags/v0_9_4/python/HepMCBrowserFrame.py
Example2:
https://gitlab.in2p3.fr/jemeuso/eusoballoon/blob/9eeb9f7bd897f003ff3a657be8bee0cabb3e4e76/EtotEtos/EUSO-TA_data_access_package_180914/etos/etoswindows/mainwindow.py
Example3:
https://www-zeuthen.desy.de/geant4/g4course2011/day3/7_analysis/analyse_8py-source.html