code: func (s *stack) NipN(idx int32) error {
  	_, err := s.nipN(idx)
  	return err
  }
docs: // NipN removes the Nth object on the stack
  //
  // Stack transformation:
  // NipN(0): [... x1 x2 x3] -> [... x1 x2]
  // NipN(1): [... x1 x2 x3] -> [... x1 x3]
  // NipN(2): [... x1 x2 x3] -> [... x2 x3]