Why does the button open two windows at once instead of one?

Question

Python

Open the program and follow this path MONDAY > REGISTRATION. When you click on the latter, two windows will pop up: MONDAY and REGISTRATION. I need to open only REGISTRATION, without MONDAY.

from tkinter import *
from tkinter import messagebox
import json
from tkinter.filedialog import asksaveasfile

root = Tk()
root.title("Organaizer")
root.resizable(0, 0)
root.configure(bg='black')
root.geometry('750x600')


def mondays():
  monles = Toplevel(root)
  monles.title("MONDAY")
  monles.resizable(0, 0)
  monles.configure(bg='black')
  monles.geometry('750x600')

  def reg1():
    monregles = Toplevel(mondays())
    monregles.title("REGISTRATION")
    monregles.resizable(0, 0)
    monregles.configure(bg='black')
    monregles.geometry('750x600')
  
  #def rl1():
  #	noterl1.pack()

  #def itgs1():
  #	noteitgs1.pack()

  #def maths1():
  #	notemaths1.pack()


  lesson = Frame(monles, width=750, height=600, bg='black')
  lesson.grid(row=0, column=0, padx=1, pady=1)


  registration = Button(lesson, text="Registration", fg='black', bg='white', font=20, width=85, height=6, command=reg1)
  registration.grid(row=0, column=0, sticky=S)

  literature = Button(lesson, text="Russian LIterature", fg='black', bg='white', font=20, width=85, height=6)
  literature.grid(row=1, column=0, sticky=S)

  itgs = Button(lesson, text="ITGS", fg='black', bg='white', font=20, width=85, height=6)
  itgs.grid(row=2, column=0, sticky=S)

  maths = Button(lesson, text="Maths", fg='black', bg='white', font=20, width=85, height=6)
  maths.grid(row=3, column=0, sticky=S)

  #notereg1 = Entry(notes, width=375, height=300, bg='white')
  #notereg1.pack()

  #noterl1 = Entry(notes, width=375, height=300, bg='white')
  #notereg1.pack()

  #noteitgs1 = Entry(notes, width=375, height=300, bg='white')
  #notereg1.pack()

  #notemath1 = Entry(notes, width=375, height=300, bg='white')
  #notereg1.pack()




lu = Frame(root, width=250, height=200, bg='white')
lu.grid(row=0, column=0, padx=1, pady=1, sticky=N)

tp = Frame(root, width=250, height=200, bg='white')
tp.grid(row=0, column=1, padx=1, pady=1, sticky=N)

ru = Frame(root, width=250, height=200, bg='white')
ru.grid(row=0, column=2, padx=1, pady=1, sticky=N)

lt = Frame(root, width=250, height=200, bg='white')
lt.grid(row=1, column=0, padx=1, pady=1, sticky=N)

md = Frame(root, width=250, height=200, bg='white')
md.grid(row=1, column=1, padx=1, pady=1, sticky=N)

rt = Frame(root, width=250, height=200, bg='white')
rt.grid(row=1, column=2, padx=1, pady=1, sticky=N)

bt = Frame(root, width=250, height=200, bg='white')
bt.grid(row=2, column=1, padx=1, pady=1, sticky=N)


mday = Button(lu, text="MONDAY", fg='black', bg='white', font=150, width=27, height=10, command=mondays)
mday.pack()

tday = Button(tp, text="TUESDAY", fg='black', bg='white', font=150, width=27, height=10)
tday.pack()

wday = Button(ru, text="WEDNESDAY", fg='black', bg='white', font=150, width=27, height=10)
wday.pack()

thday = Button(lt, text="THURSDAY", fg='black', bg='white', font=150, width=27, height=10)
thday.pack()

fday = Button(md, text="FRIDAY", fg='black', bg='white', font=150, width=27, height=10)
fday.pack()

saday = Button(rt, text="SATURDAY", fg='black', bg='white', font=150, width=27, height=10)
saday.pack()

sday = Button(bt, text="SUNDAY", fg='black', bg='white', font=150, width=27, height=10)
sday.pack()


root.mainloop()

Answer 1

Try to take out def reg1 (): from child def mondeys (): perhaps when opening one, the second one opens by "inertia". (DO NOT HIT I'm a "novice" myself)