code: public static MultiMetaDataRequest of(final List<String> quandlCodes) {
      ArgumentChecker.notNullOrEmpty(quandlCodes, "quandlCodes");
      return new MultiMetaDataRequest(quandlCodes);
    }
docs: Factory method to create a meta data request instance.
  
  @param quandlCodes the list of quandl codes for the meta data required, not null
  @return an instance of the MetaDataRequest for the given quandlCode, not null