WiringPi: using interrupts with Python

I want my RaspberryPi to perform some actions when the light in a room is switched on or off. To do so, I connected a photocell to the GPIO pins.

Previously, I used some python 3 program that queried the GPIO pin in a loop. The code looks similar to this:

import wiringpi2 as wiringpi
import time
import subprocess

subprocess.call(["gpio", "export", "24", "in"])
wiringpi.wiringPiSetupSys()

last_status = -1

while True:
    current_status = wiringpi.digitalRead(24)
    if last_status != current_status:
        last_status = current_status
        print(time.strftime("%H:%M:%S"), " -- ", current_status)
    time.sleep(1)

This works somehow, but it has some drawbacks, as the code is neither very precise nor resource-friendly.

I think using an interrupt instead of a loop might be superior in every respect. So I tried something like this:

import wiringpi2 as wiringpi
import time

wiringpi.wiringPiSetupSys()

def print_status():
    current_status = wiringpi.digitalRead(24)
    print(time.strftime("%H:%M:%S"), " -- ", current_status)

def start_interrupt():
    wiringpi.wiringPiISR(24, 2,  print_status()) # also tried "wiringpi.INT_EDGE_BOTH" instead of "2" but got the error AttributeError: 'module' object has no attribute 'INT_EDGE_BOTH'

x = wiringpi.piThreadCreate(start_interrupt())
if x != 0:
    print("it didn't start")

However, this doesn't work. I tried to find some examples on how to use WiringPi's interrupt-functionality but I failed - I only found examples for C not for Python (3).

Can you help me to get it right?

I have two questions:

• What is the right way to "translate" the loop-solution into an interrupt solution in Python (3)?
• Is there a way to use INT_EDGE_BOTH instead of some integer in Python? This would make the code more readable.