Python-сообщество

Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\Python26\lib\lib-tk\Tkinter.py", line 1410, in __call__
    return self.func(*args)
  File "C:\Python26\lib\lib-tk\Tkinter.py", line 498, in callit
    self.deletecommand(name)
  File "C:\Python26\lib\lib-tk\Tkinter.py", line 360, in deletecommand
    self._tclCommands.remove(name)
AttributeError: 'NoneType' object has no attribute 'remove'

def __init__(self, app):
	self.app=app
	self.root_harm=Toplevel()
	self.root_harm.focus_set()
	self.root_harm.transient(self.app.root)
	self.root_harm.protocol('WM_DELETE_WINDOW', self.close)
	self.root_harm.grab_set()