#заготовка для радуги
from tkinter import *

root = Tk()

Lbl = Label(width=20)

def f1(event):
    Lbl['text'] = 'красный'


btn1 = Button(width = 20, bg = 'red')
btn2 = Button(width = 20, bg = 'orange')
btn3 = Button(width = 20, bg = 'yellow')

btn1.bind('<Button-1>', f1)

Lbl.pack()
btn1.pack()
btn2.pack()
btn3.pack()

mainloop()