code: public Translation addTranslation(String locale, String value, boolean isApproximate) {
          LocaleCodeSpecification.assertCode(locale);
          if (isBlank(value)) {
              throw new IllegalArgumentException("The translation can't be blank");
          }
          Translation translation = createOrUpdateTranslation(locale, value, isApproximate);
          checkOutdatedStatus();
          return translation;
      }
docs: Saves or updates the translation for the specified locale.
  If the key was outdated, checks if the key is still outdated.
  
  @param locale        specified the translation locale
  @param value         translation value
  @param isApproximate true if the translation is not exact.
  @return the new translation
  @throws java.lang.IllegalArgumentException if the locale is null or empty
  or contains other characters than letters and "-".