Usage

pip3 install -r requirements.txt
python3 update_verifier.py lineageos4microg_pubkey /path/to/zip

On Debian/Ubuntu you can instead install the Python packages from apt:

sudo apt-get install python3-rsa python3-pyasn1
python3 update_verifier.py lineageos4microg_pubkey /path/to/zip

Note that this script requires a recent version of pyasn1 (at least 0.4.2), which is not yet present in some distributions (like Debian Stretch). In those cases, use pip3 to install the dependencies.