File "electrum/util.py", line 882, in run_with_except_hook
  File "electrum/network.py", line 1085, in run
  File "electrum/network.py", line 1067, in wait_on_sockets
  File "electrum/network.py", line 719, in process_responses
  File "electrum/network.py", line 624, in process_response
  File "electrum/network.py", line 1119, in on_notify_header
  File "electrum/blockchain.py", line 102, in can_connect
  File "electrum/blockchain.py", line 376, in can_connect
  File "electrum/blockchain.py", line 328, in get_target
  File "electrum/blockchain.py", line 295, in read_header
  File "electrum/blockchain.py", line 259, in assert_headers_file_available