public <V> boolean contains(IndexDefinition<T, V> indexDefinition, V value) {
    FieldIndex<T, V> index = (FieldIndex<T, V>) mIndices.get(indexDefinition);
    if (index == null) {
      throw new IllegalStateException("the given index isn't defined for this IndexedSet");
    }
    return index.containsField(value);
  }
@Test
  public void UniqueContains() {
    for (int i = 0; i < 3; i++) {
      assertTrue(mSet.contains(mNonUniqueIntIndex, i));
    }
    assertFalse(mSet.contains(mNonUniqueIntIndex, 4));
  }