File "electrum/gui/qt/main_window.py", line 2967, in closeEvent
  File "electrum/gui/qt/main_window.py", line 2984, in clean_up
  File "electrum/gui/qt/__init__.py", line 340, in close_window
  File "electrum/daemon.py", line 512, in stop_wallet
  File "electrum/wallet.py", line 348, in stop
  File "electrum/wallet.py", line 288, in save_db
  File "electrum/wallet_db.py", line 1204, in write
  File "electrum/wallet_db.py", line 1212, in _write
  File "electrum/util.py", line 390, in <lambda>
  File "electrum/util.py", line 386, in do_profile
  File "electrum/storage.py", line 104, in write