Как вставить гифку в окно tkinter?

import tkinter

ssw = tkinter.Tk()

def six():
    toplvl = tkinter.Toplevel() #created Toplevel widger
    photo = tkinter.PhotoImage(file = 'tenor.gif')
    lbl = tkinter.Label(toplvl ,image = photo)
    lbl.image = photo #keeping a reference in this line
    lbl.grid(row=0, column=0)

def base():
    la = tkinter.Button(ssw,text = 'yes',command=six)
    la.grid(row=0, column=0) #specifying row and column values is much better

base()

ssw.mainloop()