Tkinter Radiobutton class

from tkinter import *
from tkinter import messagebox

tk = Tk()
tk.title("Radiobuttons")
tk.geometry("100x100")

variable = StringVar()
variable.set("Male")

def show():
  messagebox.showinfo("Seleted", "You selected: %s" % variable.get())

r = Radiobutton(tk, value="Male", variable=variable, text="Male")
r2 = Radiobutton(tk, value="Female", variable=variable, text="Female")

b = Button(tk, text="Show selection", command=show)

r.pack()
r2.pack()
b.pack()

tk.mainloop()