As usual, install using pip:
$ pip install clahe # from PyPI
$ pip install git+https://github.com/anntzer/clahe # from Github
Run tests with unittest (or pytest).
This package uses a simple moving window implementation. It may be worth trying an implementation based on Perreault, S. & Hebert, P., Median Filtering in Constant Time (2007).
See also the discussion on the scikit-image issue tracker.