Python Global Variable Not Detected in Function

Question

I was doing a program so I could execute a selenium script when I pressed a button on a interface made in tkinter but I had the problem that when I runned the function that would execute the webdriver it told me that running is a local variable and I was calling it before assigning it although I assinged it as a global variable.

from selenium import webdriver
from time import sleep
from tkinter import *

root = Tk()

running = False

def start():
    if running == False:
        running = True
        browser = webdriver.Chrome("E:\\webdrivers\\chromedriver")
        browser.maximize_window()
        browser.get("https://google.com")
        print("The program is running")
    else:
        print("The program is already running")

def stop():
    if running == False:
        print("The program is not running")
    else:
        running = False
        browser.quit()
        print("Program killed")

startButton = Button(root, text="Start", padx=80, pady=80, command=start, fg="#ff0066", bg="#1a1a1a")
stopButton = Button(root, text="Stop", padx=80, pady=80, command=stop, fg="#1a1a1a", bg="#ff0066")

startButton.pack()
stopButton.pack()

root.mainloop()

Then I tried passign running as an argument but then the error is that when I use the function and change the value it changes in a local level and when I run the next function that uses that variable it has the wrong value. I would like to know how I can do to make the function recognize that variable as a global variable. Thank you all

Answer 1

I solved adding adding global before running as @formicaman told me and it looks like this if anyone needs it

from selenium import webdriver
from time import sleep
from tkinter import *

root = Tk()

running = False

def start():
    global running
    if running == False:
        running = True
        browser = webdriver.Chrome("E:\\webdrivers\\chromedriver")
        browser.maximize_window()
        browser.get("https://google.com")
        print("The program is running")
    else:
        print("The program is already running")

def stop():
    global running
    if running == False:
        print("The program is not running")
    else:
        running = False
        browser.quit()
        print("Program killed")

startButton = Button(root, text="Start", padx=80, pady=80, command=start, fg="#ff0066", bg="#1a1a1a")
stopButton = Button(root, text="Stop", padx=80, pady=80, command=stop, fg="#1a1a1a", bg="#ff0066")

startButton.pack()
stopButton.pack()

root.mainloop()