Windows Installation Instructions
Maybe it's obvious to most people but it took me a while to figure out that to install pygobject for 64bit windows / 64bit python 3.7 you need on this page:https://pygobject.readthedocs.io/en/latest/getting_started.html step 5 to be:
pacman -S mingw-w64-x86_64-gtk3 mingw-w64-x86_64-python3-gobject