code: def testMidiSignal_Args_InferredType(self):
      sig = midi_hub.MidiSignal(note=1)
      self.assertEqual(
          r"^.* channel=\d+ note=1 velocity=\d+ time=\d+.\d+$", str(sig)
      )
  
      sig = midi_hub.MidiSignal(value=2)
      self.assertEqual(
          r"^control_change channel=\d+ control=\d+ value=2 time=\d+.\d+$",
          str(sig),
      )
  
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 7 for calling the MidiHubTest obj's underlying member method code with example usage: obj.testMidiSignal_Args_InferredType() without return types