We did not cover every machine learning package available for Python. Given the limited space, we chose to focus on Scikit-learn. However, there are other options, and we list a few of them here:
A more general resource is at http://mloss.org, which is a repository of open source machine learning software. As is usually the case with repositories such as this one, the quality varies between excellent, well-maintained software and projects that were one-offs and then abandoned. It may be worth checking out if your problem is very specific and none of the more general packages address it.