Can't open serial monitor while pyserial script is working, using nodemcu

Question

I have a program which constantly sends data from Pyton to NodeMCU esp8266 (connected to the computer with a micro usb cable) using PySerial library. The program works without a problem on a mac computer but gives error on Windows computer.

Commented line is for mac, the line below is for windows.

if connect:
    #arduino = serial.Serial(port='/dev/cu.usbserial-10', baudrate=9600, timeout=.1)
    arduino = serial.Serial('COM5', 9600, timeout=.1)
    print("arduino bağlandı")

Using python, I edit data and send it constantly to the NodeMCU, the code below is in a while loop

           if connected:
                arduino.write(bytes(some_string, 'utf-8'))
                print(msj, "sent")
                time.sleep(0.1)

I've attached servo's to the NodeMCU and turn them according to the data I get from Python program.

void loop() {
  if (Serial.available()) {

    int x = Serial.read();

Later I use this x value according to my needs.

As I mentioned, the program works fine on a mac computer. However on a windows computer, I can't run both programs at the same time. If I start the python program, I get "Port monitor error: command 'open' failed: Serial port busy. Could not connect to COM5 serial port." error when I try to open the serial monitor on arduino IDE.

I've tried running the NodeMCU first but then I couldn't run the Python program.