how to go backward in computer location using python 3 code example

Example 1: python how to open a file in a different directory in mac

import os
f = open (os.path.expanduser("~/Desktop/somedir/somefile.txt"))

Example 2: windows how to store filepath as variabley python

from pathlib import Path

docs_folder = Path("some_folder/some_folder/")
text_file = docs_folder / "some_file.txt"
f = open(text_file)

#note must use forward slashes as pathlib will convert these to \\ for windows