code: func GetHolidays(countryCode string, year int) ([]Holiday, error) {
  	requiredCodes := []string{countryCode}
  	result := []Holiday{}
  
  	for len(requiredCodes) > 0 {
  		cc := requiredCodes[0]
  		hds, ok := holidayProviders[cc]
  		if !ok {
  			return nil, HolidayDataNotFoundError
  		}
  
  		requiredCodes = append(requiredCodes, hds.GetIncludes()...)
  		result = append(result, hds.GetHolidays(year)...)
  
  		requiredCodes = requiredCodes[1:]
  	}
  
  	sort.Sort(holidays(result))
  
  	return result, nil
  }
docs: // GetHolidays returns the holidays for the given ISO 3166-2 countryCode and year