The interpreter of Python can be written with Python, such as the most famous one PyPy.
There are several advantages using PyPy, like the speed, memory usage, compatibility and stackless.
In the tutorial of Allison Kaptur, the Python interpreter is a stack machine: it manipulates several stacks to perform its operations( as contrasted with a register machine, which writes to and reads from particular memory locations).
Reference:
- Allison Kaptur A Python Interpreter Written in Python)