What I tried:
brew install pygobject3 --with-python@2 gtk+3 brew install pygtk3 brew install pygobject3 pip install pygobject python -c \'import gi; gi.requ
I had the same problem. I tried
$ brew install pygobject3 gtk+3
and it was smoothly installing. Then checked as Jeff's answer:
$ python3 -c 'import gi; gi.require_version("Gtk", "3.0"); print("ok")'
got ok.
Hope this helps,
Cheers