code: @SafeVarargs
    public static boolean changed(DataSource... dataSources) {
      if (dataSources == null || dataSources.length == 0) {
        throw new InvalidOperationException("No data sources specified");
      }
      for (DataSource ds : dataSources) {
        if (ds.getDirtyStatus()) {
          return true;
        }
      }
      return false;
    }
docs: Check if given data sources are seen as changed.
  
  @param dataSources Data sources.
  @return <code>true</code> if at least one of the given data sources
  is marked as changed.
  @see #changed(DataSource)
  @see #populateIfChanged(DataSet...)