code: func GetTimeZonesForRegion(number string) ([]string, error) {
  	for i := MAX_REGION_CODE_LENGTH; i > 0; i-- {
  		index, err := strconv.Atoi(number[0:i])
  		if err != nil {
  			return nil, err
  		}
  		if CountryCodeToTimeZones[index] != nil {
  			return CountryCodeToTimeZones[index], nil
  		}
  	}
  	return []string{UNKNOWN_TIMEZONE}, nil
  }
docs: // Returns a slice of Timezones corresponding to the number passed
  // or error when it is impossible to convert the string to int
  // The algorythm tries to match the timezones starting from the maximum
  // number of phone number digits and decreasing until it finds one or reaches 0