Comment 2 for bug 1948829

Add my example in below, and attach svg file for this example. I used python3 to run this example.
----------

import os
import gi

gi.require_version("Gtk", "3.0")
gi.require_version('AppIndicator3', '0.1')

from gi.repository import Gtk as gtk
from gi.repository import AppIndicator3 as appindicator

APPINDICATOR_ID = 'myappindicator'
ICON_PATH = os.path.abspath('/home/x/linux-laptop.svg')

def main():
    indicator = appindicator.Indicator.new(APPINDICATOR_ID, ICON_PATH, appindicator.IndicatorCategory.SYSTEM_SERVICES)
    indicator.set_status(appindicator.IndicatorStatus.ACTIVE)
    indicator.set_menu(gtk.Menu())
    indicator.set_label('TEST APP', '')
    gtk.main()

if __name__ == "__main__":
    main()