File "electrum\gui\qt\network_dialog.py", line 468, in set_server
  File "electrum\network.py", line 299, 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 934, in wrapper
  File "electrum\network.py", line 600, in set_parameters
  File "electrum\simple_config.py", line 154, in set_key
  File "electrum\simple_config.py", line 163, in _set_key_in_user_config
  File "electrum\simple_config.py", line 244, in save_user_config