Transition of screens - Tkinter

Just put your components in separate frames, then you can toggle them:

import functools
import tkinter as t

class Tela(t.Frame):
    def __init__(self, parent, nome):
        t.Frame.__init__(self, parent)
        self.nome = nome
        t.Label(self, text='Voce esta na ' + self.nome).pack()

class Menu(t.Frame):
    def __init__(self, parent, *subtelas):
        t.Frame.__init__(self, parent)
        self.current_frame = self
        for subtela in subtelas:
            t.Button(subtela, text='Voltar',
                command=functools.partial(self.muda_tela, self)).pack()
            t.Button(self, text=subtela.nome, 
                command=functools.partial(self.muda_tela, subtela)).pack()

    def muda_tela(self, qual):
        self.current_frame.pack_forget()
        qual.pack()
        self.current_frame = qual

if __name__ == '__main__':
    root = t.Tk()
    root.resizable(0, 0)
    t1 = Tela(root, 'Primeira tela')
    t2 = Tela(root, 'Segunda tela')
    t3 = Tela(root, 'Terceira tela')    

    m = Menu(root, t1, t2, t3)
    m.pack()

    root.mainloop()

I wanted it when I pressed the button, another window would open according to the messages. ex: access released, the window would abir.access denied the window did not open, anyone know how to do it ?.

from tkinter import*
from tkinter import messagebox


janela = Tk()


def entra():
log = str(et1.get())
senha = str(et2.get()) 
if log == '123' and senha == '123' :
     messagebox.showinfo(title = ' login' , message  = 'acesso liberado')

root = Tk()
root.title('Menu')  
root.mainloop
else:
    messagebox.showinfo(title = ' login' , message  = 'acesso negado')

root = Tk()
root.title('Menu')  
root.mainloop





lb_titulo= Label (janela, text= ' Tela de login', font= ["Times New Roman", 30]  )
lb_titulo.pack(side = TOP )

et1= Entry(janela)
et1.place(x= 80 , y= 100 )

et2= Entry(janela )
et2.place( x= 80 , y= 140 )

lb_log= Label (janela, text= '  login:' )
lb_log.place(x= 30 , y= 100 )

lb_senha= Label (janela, text= ' senha: ')
lb_senha.place( x= 30 , y= 140 )

bt_entra= Button (janela, text = "entra" ,width = 15 ,command = entra )
bt_entra.place( x= 150 , y= 240 )






janela.title('Tela de login')
janela.geometry("400x350+300+300")
# não deixa redimecionar a tela resizable(False,False)#
janela.resizable(False,False)


janela.mainloop()