$ indicator-sound-switcher
Traceback (most recent call last):
File "/usr/local/bin/indicator-sound-switcher", line 35, in <module>
require_version('AppIndicator3', '0.1')
File "/usr/lib64/python3.6/site-packages/gi/__init__.py", line 130, in require_version
raise ValueError('Namespace %s not available' % namespace)
ValueError: Namespace AppIndicator3 not available