Traceback (most recent call last):
  File "electrum\gui\qt\main_window.py", line 2816, in closeEvent
  File "electrum\gui\qt\main_window.py", line 2734, in _show_closing_warnings
AttributeError: 'ElectrumWindow' object has no attribute 'closing_warning_callbacks'. Did you mean: 'register_closing_warning_callback'?