File "/usr/local/lib/python3.7/site-packages/trezorlib/client.py", line 117, in cancel
    self._raw_write(messages.Cancel())
  File "/usr/local/lib/python3.7/site-packages/trezorlib/client.py", line 126, in _raw_write
    self.transport.write(msg)
  File "/usr/local/lib/python3.7/site-packages/trezorlib/transport/bridge.py", line 164, in write
    self.handle.write_buf(header + ser)
  File "/usr/local/lib/python3.7/site-packages/trezorlib/transport/bridge.py", line 68, in write_buf
    self.transport._call("post", data=buf.hex())
  File "/usr/local/lib/python3.7/site-packages/trezorlib/transport/bridge.py", line 132, in _call
    return call_bridge(uri, data=data)
  File "/usr/local/lib/python3.7/site-packages/trezorlib/transport/bridge.py", line 45, in call_bridge
    raise TransportException(error_str)