Traceback (most recent call last):
  File "electrum/gui/qt/util.py", line 1492, in on_qt_callback_signal
  File "electrum/gui/qt/main_window.py", line 503, in on_event_status
  File "electrum/gui/qt/main_window.py", line 1075, in update_status
  File "electrum/wallet.py", line 1173, in get_balances_for_piechart
  File "electrum/wallet.py", line 1088, in get_balance
  File "electrum/util.py", line 1262, in func_wrapper
  File "electrum/address_synchronizer.py", line 546, in f
  File "electrum/address_synchronizer.py", line 928, in get_balance
TypeError: unsupported operand type(s) for +=: 'int' and 'str'