title: Invalid command name while executing ("after" script)
body: <p>As solve this problem? I'm running this code, window is created, but in console appears message on the error. I think problem the fact that is "after" loop not terminate but the window already destroyed.</p>
  
  <p>Code:</p>
  
  <pre><code>import Tkinter as tk
  import time
  
  class App():
      def __init__(self):
          self.root = tk.Tk()
          self.label = tk.Label(text="")
          self.label.pack()
          self.update_clock()
          self.root.mainloop()
  
      def update_clock(self):
          now = time.strftime("%H:%M:%S")
          self.label.configure(text=now)
          self.root.after(1000, self.update_clock)
  
  app=App()
  </code></pre>
  
  <p>A message in console:</p>
  
  <pre><code>invalid command name "66120320callit"
  while executing
  "66120320callit"
  ("after" script)
  </code></pre>
  
  <p>Sorry for my small information in first post. I'm using Spyder IDE, and bugs see in spyder console, wherein run repeatedly my code. A description this bugs I find in the python bug tracker as "wait_variable hangs at exit"</p>