File "electrum/gui/qt/main_window.py", line 3018, in closeEvent
  File "electrum/gui/qt/main_window.py", line 3035, in clean_up
  File "electrum/gui/qt/__init__.py", line 338, in close_window
  File "electrum/daemon.py", line 525, in stop_wallet
  File "electrum/wallet.py", line 353, in stop
  File "electrum/wallet.py", line 302, in save_db
  File "electrum/wallet_db.py", line 1239, in write
  File "electrum/wallet_db.py", line 1247, in _write
  File "electrum/util.py", line 408, in <lambda>
  File "electrum/util.py", line 404, in do_profile
  File "electrum/storage.py", line 85, in write