pypi UserWarning: Unknown distribution option: 'install_requires'

python setup.py uses distutils which doesn't support install_requires. setuptools does, also distribute (its successor), and pip (which uses either) do. But you actually have to use them. I.e. call setuptools through the easy_install command or pip install.

Another way is to import setup from setuptools in your setup.py, but this not standard and makes everybody wanting to use your package have to have setuptools installed.