There are various method through which one can achieve installation of the module in python and same also applicable to XmlCli as well.
python -m pip install xmlcli --proxy <proxy-url> --index-url <self-hosted-pypi-index>
python -m pip install <xmlcli-x.x.x.whl> --proxy <proxy-url>
python -m pip install <repo-url> --proxy <proxy-url>
python -m pip install git+https://github.com/intel/xml-cli