code: public void addLanguages( Iterable<QueryParser> languages ) {
          CheckArg.isNotNull(languages, "languages");
          for (QueryParser language : languages) {
              addLanguage(language);
          }
      }
docs: Add one or more languages to this engine by supplying the corresponding parsers.
  
  @param languages the query parsers for the languages that are to be added
  @throws IllegalArgumentException if the iterable reference is null