Checkbox-snappy build failing gir1.2-gtk3.0

i am trying to build the checkbox adding python import for gir1.2-gtk3.0, but the build is failing , please suggest

snap/snapcraft.yaml

python-import:
plugin: python
python-packages:
- gir1.2-gtk-3.0


Usage:
/build/checkbox-snappy/stage/usr/bin/python3 -m pip list [options]

no such option: --format
You are using pip version 8.1.1, however version 10.0.1 is available.
You should consider upgrading via the ‘pip install --upgrade pip’ command.
Collecting gir1.2-gtk-3.0
Could not find a version that satisfies the requirement gir1.2-gtk-3.0 (from versions: )
No matching distribution found for gir1.2-gtk-3.0

Downloading parts list
Failed to run ‘/build/checkbox-snappy/stage/usr/bin/python3 -m pip download --disable-pip-version-check --dest /build/checkbox-snappy/parts/python-import/python-packages gir1.2-gtk-3.0’: Exited with code 1.
here is the detailed build log

https://launchpadlibrarian.net/372279003/buildlog_snap_ubuntu_xenial_arm64_checkbox-6309p2_BUILDING.txt.gz