You can read John Shipman's nicely-written pure-Python implementation, which even includes detailed explanations on how he built it, from the top-level design down to how the classes were implemented, including things like a discussion on how to provide a nice Pythonic interface.
You can also search PyPI, where there are multiple additional implementations.
Or you can read the Wikipedia entry or the original paper, both of which have detailed explanations and pseudocode that you can translate into Python.
Your existing question is way too general. But if, after reading the relevant information, you have specific questions ("What does this part of Shipman's code do", "What does this line of pseudocode in Pugh's paper means, and how do I translate it to Python", "What exactly is a 'cut list'", etc.), then you can ask on SO.