This kind of question can easily be answered with a quick Google search. But, I would like to ask you why you want to do it?
Python is an open-source programming language and is actively contributed to. If you wish to contribute, visit
Python Developer's Guide[
^]. You will find all the resources for this. Read the
contributor's guide[
^].
If you meant to create a new project (that is branched off), make sure you read the
LICENSE[
^] and know what are your rights. This can impact whether you can run the Python without contributing back to the open-source.