If statement with or operator

Wed Feb 22 12:03:31 EST 2017

Hello Friends,
I need suggestion on the if statement in the below code , all that I was
trying to do was to add a check i.e if any one of the functions return
True then break the loop.
 end_time = time.time() + 300
 umount_completed = False
 while time.time() < end_time:
 if attempt_umount() is True or df_output_lines() is True:
 logging.info("umount completed sucessfully")
 umount_completed = True
 break
 time.sleep(15)
 assert umount_completed, "ERROR: The umount failed Exiting"
Can this be optimized better , please suggest. I am on Linux and Python
2.7
Regards.
Ganesh