code: def gold_iterator(transpose_range=(0, 1)):
      """Iterates through pairs of MIDI notes and buttons."""
      maxlen = gold_longest()
      for transpose in range(*transpose_range):
          for midi_notes, buttons in _GOLD:
              midi_notes = [
                  int(x) + transpose for x in midi_notes.split(",")
              ]
              buttons = [int(x) for x in list(buttons)]
              seqlen = len(midi_notes)
              assert len(buttons) == len(midi_notes)
              assert seqlen <= maxlen
              midi_notes += [21] * (maxlen - seqlen)
              buttons += [0] * (maxlen - seqlen)
              yield [midi_notes], [buttons], seqlen
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
label_desc: Use image node_id 2 for calling a global function with example usage: gold_iterator(transpose_range) without return types