code: def testPassThrough_Poly(self):
      self.midi_hub.passthrough = False
      self.send_capture_messages()
      self.assertTrue(self.port.message_queue.empty())
      self.midi_hub.passthrough = True
      self.send_capture_messages()
  
      passed_messages = []
      while not self.port.message_queue.empty():
          passed_messages.append(self.port.message_queue.get().bytes())
      self.assertListEqual(
          passed_messages, [m.bytes() for m in self.capture_messages]
      )
  
imports: import collections
  import queue
  import threading
  import time
  from magenta.common import concurrency
  from magenta.interfaces.midi import midi_hub
  import mido
  from note_seq import testing_lib
  from note_seq.protobuf import music_pb2
  import tensorflow.compat.v1
label_desc: Use image node_id 24 for calling the MidiHubTest obj's underlying member method code with example usage: obj.testPassThrough_Poly() without return types