import tkinter as tki

class MyApp:
    def __init__(self,root):

        top_frame = tki.Frame(root)
        bottom_frame = tki.Frame(root)
        top_frame.pack()
        bottom_frame.pack()

        for i in range(4):
            b = tki.Button(top_frame,text=str(i))
            b.pack(side = tki.LEFT)
            b = tki.Button(bottom_frame,text=str(i))
            b.pack(side = tki.LEFT)

root = tki.Tk()
MyApp(root)
root.mainloop()