Traceback (most recent call last):
  File "electrum\gui\qt\my_treeview.py", line 491, in showEvent
  File "electrum\gui\qt\history_list.py", line 520, in update
  File "electrum\util.py", line 495, in do_profile
  File "electrum\gui\qt\history_list.py", line 300, in refresh
  File "electrum\util.py", line 495, in do_profile
  File "electrum\wallet.py", line 1443, in get_full_history
  File "electrum\wallet.py", line 1226, in get_onchain_history
  File "electrum\util.py", line 1242, in func_wrapper
  File "electrum\address_synchronizer.py", line 548, in f
  File "electrum\address_synchronizer.py", line 584, in get_history
  File "electrum\util.py", line 1242, in func_wrapper
  File "electrum\address_synchronizer.py", line 548, in f
  File "electrum\address_synchronizer.py", line 911, in get_balance
TypeError: sequence item 0: expected str instance, NoneType found