code: def transpose(obj, semitone):
      
      _check_supported(obj)
      copied = deepcopy(obj)
      copied.transpose(semitone)
      return copied
docs: Return a copy of the object with piano-roll(s) transposed by `semitones`
      semitones.
  
      Parameters
      ----------
      semitone : int
          Number of semitones to transpose the piano-roll(s).