Histographs { public static <K extends Comparable<K>> long sum( Histograph<K> histograph ) { long result = 0; for ( K key : histograph.keySet() ) { result += histograph.get( key ); } return result; }  static Histograph<K> intersection( Histograph<K> h0, Histograph<K> h1 ); static Histograph<K> union( Histograph<K> h0, Histograph<K> h1 ); static long sum( Histograph<K> histograph );  }
@Test public void testSum() throws Exception { }