input: Write a python function to create a Tkinter window with two buttons labeled "Stop Program" and "Start Program", and display the window.
  assert check_buttons() == ["Stop Program", "Start Program"]
output: def check_buttons():
      import tkinter as tk
  
      def create_window():
          window = tk.Tk()
          stop_button = tk.Button(window, text="Stop Program")
          start_button = tk.Button(window, text="Start Program")
          stop_button.pack()
          start_button.pack()
          return window
  
      window = create_window()
      buttons = [button.cget("text") for button in window.winfo_children() if isinstance(button, tk.Button)]
      window.destroy()
      return buttons