Traceback (most recent call last):
  File "trezorlib/client.py", line 153, in cancel
  File "trezorlib/client.py", line 171, in _raw_write
  File "trezorlib/transport/protocol.py", line 107, in write
  File "trezorlib/transport/protocol.py", line 134, in write
  File "trezorlib/transport/webusb.py", line 78, in write_chunk
AssertionError