### Question:
Constructor implements TreeConstructor<E, MutableNode<E>, PathCopyTree<E>> { @Override public Class<? extends Tree> forClass() { return PathCopyTree.class; }  @Override PathCopyTree<E> build(E e, PathCopyTree<E>[] subtrees); @Override Class<? extends Tree> forClass();  }### Answer:
@Test public void key() { final Constructor<String> constructor = new Constructor<>(); assertEquals(PathCopyTree.class, constructor.forClass()); }