File "/tmp/.mount_electrdWYFaW/usr/lib/python3.7/site-packages/electrum/gui/qt/main_window.py", line 3018, in closeEvent
    self.clean_up()
  File "/tmp/.mount_electrdWYFaW/usr/lib/python3.7/site-packages/electrum/gui/qt/main_window.py", line 3024, in clean_up
    self.config.set_key("is_maximized", self.isMaximized())
  File "/tmp/.mount_electrdWYFaW/usr/lib/python3.7/site-packages/electrum/simple_config.py", line 160, in set_key
    self._set_key_in_user_config(key, value, save)
  File "/tmp/.mount_electrdWYFaW/usr/lib/python3.7/site-packages/electrum/simple_config.py", line 169, in _set_key_in_user_config
    self.save_user_config()
  File "/tmp/.mount_electrdWYFaW/usr/lib/python3.7/site-packages/electrum/simple_config.py", line 262, in save_user_config
    f.write(s)