Stopwatch.py

import tkinter as tk
from time import time

class Stopwatch:
    def __init__(self, timeElapsed, paused, window, button):

        self.timeElapsed = timeElapsed
        self.window = window
        self.paused = paused
        print('out')

    def toggle(self):
        if self.paused:
            self.paused = False
            #self.button.config(text='Stop')
            self.oldtime = time()
            self.run_timer()
        else:
            self.paused = True
            self.oldtime = time()

    def run_timer(self):
        if self.paused:
            return
        delta = int(time() - self.oldtime)
        timestr = '{:02}:{:02}'.format(*divmod(delta, 60))
        self.timeElapsed.config(text=timestr)
        self.timeElapsed.after(1000, self.run_timer)