from threading import Timer
from datetime import datetime
sep = ' : '
quit_sys = 0
hour = datetime.now().hour
minute = datetime.now().minute
def tick():
    global sep
    global out_clock
    global quit_sys
    global minute
    global hour
    if quit_sys == 0:
        if round(datetime.now().second) != 0:
            if sep == ' : ':
                out_clock = out_clock.replace(sep, '   ', 1)
                text_clock.delete(1.0, END)
                text_clock.insert(1.0, out_clock, 'clock')
                sep = '   '
            else:
                out_clock = out_clock.replace(sep, ' : ')
                text_clock.delete(1.0, END)
                text_clock.insert(1.0, out_clock, 'clock')
                sep = ' : '
        else:
            minute = datetime.now().minute
            hour = datetime.now().hour
            check_zero()
            if minute == 0 and hour == 0:
                day = datetime.now().day
                mounth = mounts_dict[datetime.now().month]
                year = datetime.now().year
                day_week = week_dict[datetime.now().weekday()]
                out_calend = f"{day} {mounth} {year}\n{day_week}"
                text_calendar.delete(1.0, END)
                text_calendar.insert(1.0, out_calend, 'clock')
                out_clock = f"{hour}{sep}{minute}"
                text_clock.delete(1.0, END)
                text_clock.insert(1.0, out_clock, 'clock')
            else:
                out_clock = f"{hour}{sep}{minute}"
                text_clock.delete(1.0, END)
                text_clock.insert(1.0, out_clock, 'clock')
                
        Timer(1, tick).start()

  
import tkinter as tk
import datetime
def show_time():
    t = datetime.datetime.now()
    sv.set(f'{t.hour}:{t.minute:02}:{t.second:02}')
    root.after(1000, show_time)
root = tk.Tk()
sv = tk.StringVar()
lbl = tk.Label(textvariable=sv, font='Arial 32 bold')
lbl.pack()
show_time()
root.mainloop()

 Timer(1, tick).start()