### Question:
StatementCommons { public static <T extends Statement> Set<T> newTripleSet() { return new FastSet<>(equivalenceEquality(tripleEquivalence())); }  static Equivalence<Statement> tripleEquivalence(); static Equivalence<Statement> quadrupleEquivalence(); static Set<T> newTripleSet(); static Set<T> newQuadrupleSet(); static Map<K,V> newTripleMap(); static Map<K,V> newQuadrupleMap();  }### Answer:
@Test public void testTripleSet() { Set<Statement> set = StatementCommons.newTripleSet(); set.add(stmt1); Assert.assertTrue(set.contains(stmt2)); set.add(stmt2); Assert.assertEquals(1,set.size()); Assert.assertFalse(set.contains(stmt3)); set.add(stmt3); Assert.assertEquals(2,set.size()); }