add something to path with python code example

Example 1: edit path variable using python

app_path = os.path.join(root_path, 'other', 'dir', 'to', 'app')
os.environ["PATH"] += os.pathsep + app_path

Example 2: add python to path windows 10

Either manually change it by doing the steps for the answer by skilliboi.

Or you can reinstall python and when you do that, make sure to tick the box that says:
Add python to PATH (or something like that)