First of all you should go to the function download_latest and change the download directory path to the one you prefer (along the lines of with open(f'C:/{%path_to_file%}/python-...
This is a very simple and fast script that checks your Python 3 version that you have installed, and if needed downloads an updated version (You will still have to manually install it, though).
Note
The version downloaded is for amd 64 windows 10. You can change the URL in download_latest function, python_url variable.