code: public DataStore getDataStore(final Collection<String> columns) {
          for (DataStore ds : dataBatches) {
              if (ds.hasColumns(columns)) {
                  return ds;
              }
          }
          return null;
      }
docs: Get the DataStore associated with a collection of column names.
  
  @param columns Collection of columns to find a corresponding DataStore for.
  @return DataStore corresponding to the columns, or null if not found.