where does python check for file in file handling code example

Example 1: file exist python

import os.path

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

Example 2: python check if file exists

#using pathlib
from pathlib import Path

file_name = Path("file.txt")
if file_name.exists():
    print("exists") 
else:
    print("does not exist")