code: public String getQuandlCode() {
      try {
        String dataSourceField = getString(DATA_SOURCE_FIELD);
        String codeField = getString(CODE_FIELD);
        // if either not present, will throw an exception.
        return dataSourceField + "/" + codeField;
      } catch (RuntimeException ex) {
        return null;
      }
    }
docs: Get the Quandl code associated with this metadata.
  
  @return the quandl code (DATASOURCE/CODE form), null if not present.