File "site-packages\electrum-3.1.2-py3.5.egg\electrum_gui\qt\main_window.py", line 2996, in closeEvent
  File "site-packages\electrum-3.1.2-py3.5.egg\electrum_gui\qt\main_window.py", line 3013, in clean_up
  File "site-packages\electrum-3.1.2-py3.5.egg\electrum_gui\qt\__init__.py", line 248, in close_window
  File "site-packages\electrum-3.1.2-py3.5.egg\electrum\simple_config.py", line 278, in save_last_wallet
  File "site-packages\electrum-3.1.2-py3.5.egg\electrum\simple_config.py", line 140, in set_key
  File "site-packages\electrum-3.1.2-py3.5.egg\electrum\simple_config.py", line 149, in _set_key_in_user_config
  File "site-packages\electrum-3.1.2-py3.5.egg\electrum\simple_config.py", line 215, in save_user_config