Python + Gnome

I’m building a python app that has UI and it’s going to use cairo (so I need to be able to run pkg-config), what would be the snapcraft config for it? I read the documentation for GTK4, Gnome extension and Python app and there’s no mention for this use case or for using libadwaita.

Not sure how helpful will be but this is the snapcraft.yml I made so far (failing):

name: tasker
summary: Simple task app to remember what you did # 79 char long summary
description: App the uses an external MongoDB to store and find everything you did previous days

base: core22
version: '1.0'
grade: stable
confinement: strict

parts:
  tasker:
    plugin: python
    source: .
    python-packages:
      - .

apps:
  tasker:
    command: bin/tasker_gtk
    extensions: [gnome]

slots:
  tasker:
    interface: dbus
    bus: session
    name: org.gnome.Tasker