title: Are built-in types implementations avaliable in Python?
body: <p>It's easy to find implementation of any library module in python (you just go to CPython repository on Github: <a href="https://github.com/python/cpython/" rel="nofollow noreferrer">https://github.com/python/cpython/</a>), but where could I find implementations of build-in CPython types? It's important for example to prove that <strong>complex</strong> build-in type is inherited from <strong>numbers.Complex</strong> abc. Or it is also could be useful to explore attributes of <strong>function</strong> type.</p>