Example showing file handle being re-used...

filehandle.py

import os

f = os.open('file1.txt', os.O_RDWR | os.O_CREAT)
print("Handle1: {!r}".format(f))
os.close(f)

f = open('file2.txt', 'w+b')
print("Handle2: {!r}".format(f.fileno()))
f.close()