code: func (s *Sheet) AddRowAtIndex(index int) (*Row, error) {
  	if index < 0 || index > len(s.Rows) {
  		return nil, errors.New("AddRowAtIndex: index out of bounds")
  	}
  	row := &Row{Sheet: s}
  	s.Rows = append(s.Rows, nil)
  
  	if index < len(s.Rows) {
  		copy(s.Rows[index+1:], s.Rows[index:])
  	}
  	s.Rows[index] = row
  	if len(s.Rows) > s.MaxRow {
  		s.MaxRow = len(s.Rows)
  	}
  	return row, nil
  }
docs: // Add a new Row to a Sheet at a specific index