code: func (s *stack) PickN(n int32) error {
  	so, err := s.PeekByteArray(n)
  	if err != nil {
  		return err
  	}
  	s.PushByteArray(so)
  
  	return nil
  }
docs: // PickN copies the item N items back in the stack to the top.
  //
  // Stack transformation:
  // PickN(0): [x1 x2 x3] -> [x1 x2 x3 x3]
  // PickN(1): [x1 x2 x3] -> [x1 x2 x3 x2]
  // PickN(2): [x1 x2 x3] -> [x1 x2 x3 x1]