title: How to close a current window and open a new window at the same time?
body: <p>This code opens a button, which links to another button. The other button can close its self, but the first button can't close itself and open a new one at the same time, How do I fix this?</p>
  
  <pre><code>import tkinter as tk
  
  class Demo1:
      def __init__(self, master):
          self.master = master
          self.frame = tk.Frame(self.master)
          self.HelloButton = tk.Button(self.frame, text = 'Hello', width = 25, command = self.new_window,)
          self.HelloButton.pack()
          self.frame.pack()
      def close_windows(self):
          self.master.destroy()
          self.new_window
      def new_window(self):
          self.new_window = tk.Toplevel(self.master)
          self.app = Demo2(self.new_window)
  
  
  class Demo2:
      def __init__(self, master):
          self.master = master
          self.frame = tk.Frame(self.master)
          self.quitButton = tk.Button(self.frame, text = 'Quit', width = 25, command = self.close_windows)
          self.quitButton.pack()
          self.frame.pack()
      def close_windows(self):
          self.master.destroy()
  
  def main(): 
      root = tk.Tk()
      app = Demo1(root)
      root.mainloop()
  
  if __name__ == '__main__':
      main()
  </code></pre>