After poking around a bit through the Introduction to Tkinter, I came up with the code below, which doesn't do anything except display a text field and clear it when the "Clear text" button is pushed:
import tkinter as tk
class App(tk.Frame):
def __init__(self, master):
tk.Frame.__init__(self, master, height=42, width=42)
self.entry = tk.Entry(self)
self.entry.focus()
self.entry.pack()
self.clear_button = tk.Button(self, text="Clear text", command=self.clear_text)
self.clear_button.pack()
def clear_text(self):
self.entry.delete(0, 'end')
def main():
root = tk.Tk()
App(root).pack(expand=True, fill='both')
root.mainloop()
if __name__ == "__main__":
main()