python-bertini is a Python library for numerical algebraic geometry. Mostly, it's just a wrapper around Bertini (sold separately).
Don't install python-bertini. It's not ready yet. If you want something right now, and you're into Julia, you might try Bertini.jl.
If you absolutely must, then clone this repository, cd to the base directory, and run either
$ conda env create -n bertini -f environment.yml # if you have anaconda
or (with your virtualenv activated)
$ pip install -U -r requirements.txt # if you just want to use a virtualenv
Then in either case run
$ pip install -e .