File "electrum/gui/qt/main_window.py", line 3003, in closeEvent
  File "electrum/gui/qt/main_window.py", line 3020, in clean_up
  File "electrum/gui/qt/__init__.py", line 340, in close_window
  File "electrum/daemon.py", line 524, in stop_wallet
  File "electrum/wallet.py", line 344, in stop
  File "electrum/wallet.py", line 293, in save_db
  File "electrum/wallet_db.py", line 1224, in write
  File "electrum/wallet_db.py", line 1232, in _write
  File "electrum/util.py", line 406, in <lambda>
  File "electrum/util.py", line 402, in do_profile
  File "electrum/storage.py", line 86, in write