File "electrum\gui\qt\network_dialog.py", line 459, in set_server
  File "electrum\network.py", line 287, in run_from_another_thread
  File "concurrent\futures\_base.py", line 432, in result
  File "concurrent\futures\_base.py", line 384, in __get_result
  File "electrum\util.py", line 910, in wrapper
  File "electrum\network.py", line 561, in set_parameters
  File "electrum\simple_config.py", line 149, in set_key
  File "electrum\simple_config.py", line 158, in _set_key_in_user_config
  File "electrum\simple_config.py", line 238, in save_user_config