code: def main(unused_argv):
      tf.logging.set_verbosity(FLAGS.log)
  
      if not _validate_flags():
          return
  
      # Load generators.
      generators = []
      for bundle_file in FLAGS.bundle_files.split(","):
          generators.append(
              _load_generator_from_bundle_file(bundle_file)
          )
          if generators[-1] is None:
              return
  
      # Initialize MidiHub.
      hub = midi_hub.MidiHub(
          FLAGS.input_ports.split(","),
          FLAGS.output_ports.split(","),
          midi_hub.TextureType.POLYPHONIC,
          passthrough=FLAGS.passthrough,
          playback_channel=FLAGS.playback_channel,
          playback_offset=FLAGS.playback_offset,
      )
  
      control_map = {
          re.sub(
              "_control_number$", "", six.ensure_str(f)
          ): FLAGS.__getattr__(f)
          for f in _CONTROL_FLAGS
      }
      if FLAGS.learn_controls:
          CCMapper(control_map, hub).update_map()
  
      if control_map["clock"] is None:
          # Set the tick duration to be a single bar, assuming a 4/4 time signature.
          clock_signal = None
          tick_duration = 4 * (60.0 / FLAGS.qpm)
      else:
          clock_signal = midi_hub.MidiSignal(
              control=control_map["clock"], value=127
          )
          tick_duration = None
  
      def _signal_from_control_map(name):
          if control_map[name] is None:
              return None
          return midi_hub.MidiSignal(
              control=control_map[name], value=127
          )
  
      end_call_signal = _signal_from_control_map("end_call")
      panic_signal = _signal_from_control_map("panic")
      mutate_signal = _signal_from_control_map("mutate")
  
      metronome_channel = (
          FLAGS.metronome_channel if FLAGS.enable_metronome else None
      )
      interaction = midi_interaction.CallAndResponseMidiInteraction(
          hub,
          generators,
          FLAGS.qpm,
          FLAGS.generator_select_control_number,
          clock_signal=clock_signal,
          tick_duration=tick_duration,
          end_call_signal=end_call_signal,
          panic_signal=panic_signal,
          mutate_signal=mutate_signal,
          allow_overlap=FLAGS.allow_overlap,
          metronome_channel=metronome_channel,
          min_listen_ticks_control_number=control_map[
              "min_listen_ticks"
          ],
          max_listen_ticks_control_number=control_map[
              "max_listen_ticks"
          ],
          response_ticks_control_number=control_map["response_ticks"],
          tempo_control_number=control_map["tempo"],
          temperature_control_number=control_map["temperature"],
          loop_control_number=control_map["loop"],
          state_control_number=control_map["state"],
      )
  
      _print_instructions()
  
      interaction.start()
      try:
          while True:
              time.sleep(1)
      except KeyboardInterrupt:
          interaction.stop()
  
      print("Interaction stopped.")
  
imports: import functools
  import re
  import threading
  import time
  from magenta.interfaces.midi import midi_hub
  from magenta.interfaces.midi import midi_interaction
  from magenta.models.drums_rnn import drums_rnn_sequence_generator
  from magenta.models.melody_rnn import melody_rnn_sequence_generator
  from magenta.models.performance_rnn import performance_sequence_generator
  from magenta.models.pianoroll_rnn_nade import pianoroll_rnn_nade_sequence_generator
  from magenta.models.polyphony_rnn import polyphony_sequence_generator
  from magenta.models.shared import sequence_generator_bundle
  import six
  import tensorflow.compat.v1
label_desc: Use image node_id 4 for calling a global function with example usage: main(unused_argv) and returns: midi_hub, None