open file (e.g. right click/ open with) event for python3 script on a mac

Question

I would like my python3 script to react to an open file event. Is there any way to achieve that? The following python3 script is named example

#!/path/to/python3

from PyQt5.QtWidgets import QApplication, QWidget

def window():
   app = QApplication(sys.argv)
   widget = QWidget()

   widget.setWindowTitle("Simple example")
   widget.show()
   sys.exit(app.exec_())

if __name__ == '__main__':
   window()

I generated the following directories to form a bundle:

example.app/
-- Contents/
   -- Info.plist
   -- MacOS/
      -- example

The Info.plist file:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>CFBundleExecutable</key>
    <string>example</string>
</dict>
</plist>

However, while I can execute it by, e.g., double clicking the .app file itself, I could not have it react to 'open file'.

The following apple script wrapper works, but is quite ugly:

on open theDroppedItems
    repeat with a from 1 to length of theDroppedItems
        set theCurrentDroppedItem to item a of theDroppedItems
        set posixfile to (POSIX path of theCurrentDroppedItem)
        # display dialog posixfile
        do shell script "/path/to/python3 /path/to/python3script " & posixfile
    end repeat
end open

It 'converts' open file to a command line argument. Supposedly, Qt could work and Tk as well (l.90), but I could not find a simple example implementing it.