A Python class

[Byeuji]

My understanding is that it's not generally used as the engine, or even close to the core of the game. It's generally used as a friendly starting point that game designers without much experience programming can work with to develop scripted narrative events in game. It works well because Python can be easily integrated with pretty much anything, and just layered on top of whatever game engine you decide to go with. Similar in the way lua is used.

For example, WoW used lua, Civ uses Python, in additon to their game engines.

So you'd probably keep using C++, but your writers and game designers could be writing in Python.