what python library is used to check for the existence of a directory code example

Example 1: how to check whether file exists in python

import os.path

if os.path.isfile('filename.txt'):
    print ("File exist")
else:
    print ("File not exist")

Example 2: python os if file exists

import os.path

if os.path.isfile('filename.txt'):
    print ("File exist")
else:
    print ("File not exist")