code: def _CreateSyntheticSequence(self):
      seq = music_pb2.NoteSequence(total_time=10)
      testing_lib.add_track_to_sequence(seq, 0, [(50, 20, 0, 5)])
      testing_lib.add_track_to_sequence(seq, 0, [(50, 80, 5, 10)])
      return seq
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from magenta.models.onsets_frames_transcription import audio_label_data_utils
  from note_seq import audio_io
  from note_seq import constants
  from note_seq import testing_lib
  from note_seq.protobuf import music_pb2
  import numpy
  import tensorflow.compat.v1
label_desc: Use image node_id 1 for calling the SplitAudioTest obj's underlying member method code with example usage: obj._CreateSyntheticSequence() and returns: seq