File "electrum\gui\qt\main_window.py", line 1579, in do_pay
  File "electrum\wallet.py", line 730, in save_invoice
  File "electrum\wallet.py", line 288, 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 390, in <lambda>
  File "electrum\util.py", line 386, in do_profile
  File "electrum\storage.py", line 94, in write