Ref https://wiki.gnome.org/Projects/PyGObject/Threading
"The requirement to call GObject.threads_init() has been removed from
PyGObject 3.10.2 when using Python native threads with GI (via the
threading module) as well as with GI repositories which manage their own
threads that may call back into Python (like GStreamer callbacks). The
GObject.threads_init() function will still exist for the entire 3.x
series for compatibility reasons but emits a deprecation warning."