Raspberry Pi Quadrascopic Camera

import os
import time
from gpiozero import Button
from datetime import datetime
from signal import pause
from multiprocessing import Process, Queue
from gpiozero import CPUTemperature
from subprocess import Popen

shutterButton = Button(20)
PreviewButton = Button(26)
shutdownButton = Button(21)
cpu = CPUTemperature()
x = 0
sleepStaus = 0
k = None
startTimer = 0

def sleepFunction():
    command = "xset dpms force off"
    cmd = command
    p = Popen(cmd.split())
    print("screen off")


def run():
    print("preview is initiated")
    try:
        temperature = cpu.temperature
        command = "libcamera-hello -t 5000 --autofocus --info-text Preview_Display"
        cmd = command
        p = Popen(cmd.split())
        x = p.pid
        print("Process ID:", x)
        while True:
            if p.poll() != None:
                print("preview is closed")
                break;
            else:
                print("waiting for it to take picture")
    except:
        print("error")

def WorkerThread():
    print("capture is initiated")
    # command = "kill "+ str(x)
    # cmd = command
    # p = Popen(cmd.split())
    try:
        location = "/media/pi/SD/"
        name = datetime.now().strftime("%Y_%m_%d_%H_%M_%S")
        command = "libcamera-still -t 3000 -o "+name+".jpg --autofocus --info-text Image_Capture"
        cmd = command
        r = Popen(cmd.split())
        k = r.pid
        print(r.poll())
        while True:
            if r.poll() != None:
                print("image capture is closed")
                break;
            else:
                print("waiting for it to take picture")
    except:
        print("error")

while True:
    if (shutterButton.is_pressed == True):
        WorkerThread()
        time.sleep(1)

    elif (PreviewButton.is_pressed == True):
        run()
        time.sleep(1)

    elif (shutdownButton.is_pressed == True):
        pressed_time=time.monotonic()
        while (shutdownButton.is_pressed == True): 
            pass
        pressed_time=time.monotonic()-pressed_time
        if pressed_time<5:
            print("shutdownButton is pressed less then 5 sec")
            sleepFunction()
            time.sleep(0.05)
        elif pressed_time>=5: 
            print("shutdownButton is pressed more then 5 sec")       
            command = "sudo shutdown -h now"
            cmd = command
            p = Popen(cmd.split())
            time.sleep(0.05)