To run this script you should set the following environment properly or provide other credencial setup as required by boto3 library - http://boto3.readthedocs.io/en/latest/guide/configuration.html
AWS_ACCESS_KEY_ID=<ACCESS_KEY>
AWS_SECRET_ACCESS_KEY=<SECRET_ACCESS_KEY>
You need python3 to run this script. It's recommended to use a virtualenv (virtualenvwrapper #FTW).
python -m virtualenv --python=$(which python3) venv
source venv/bin/activate
pip install -r requirements.txt
python iam-users.py --help
Usage: iam_users.py [OPTIONS]
Options:
-p, --pretty easier for humans read
--filename FILENAME Save output to a file instead of stdout
-v, --verbose Set verbosity level (use twice to increase)
--help Show this message and exit.