* Returns the identity function.
   *
   * <p><b>Discouraged:</b> Prefer using a lambda like {@code v -> v}, which is shorter and often
   * more readable.
   */
  // implementation is "fully variant"; E has become a "pass-through" type
  @SuppressWarnings("unchecked")
  public static <E extends @Nullable Object> Function<E, E> identity() {
    return (Function<E, E>) IdentityFunction.INSTANCE;
  }

  // enum singleton pattern

  private enum SupplierFunctionImpl implements SupplierFunction<@Nullable Object> {
    INSTANCE;

    // Note: This makes T a "pass-through type"
    @Override
    public @Nullable Object apply(Supplier<@Nullable Object> input) {
      return input.get();
    }

    @Override
    public String toString() {

// You must use TF_AddInput() for the first input (since it takes a
// single tensor), and TF_AddInputList() for the second input (since
// it takes a list, even if you were to pass a list with a single
// tensor), as in:
//   TF_OperationDescription* desc = TF_NewOperation(graph, "Concat", "c");
//   TF_Output concat_dim_input = {...};
//   TF_AddInput(desc, concat_dim_input);

---

„_Ich bin überglücklich mit **FastAPI**. Es macht so viel Spaß!_“

      for (TwoArg.Action second : TwoArg.Action.values()) {
        TwoArg bar = new TwoArg(first, second);
        if (first.equals(TwoArg.Action.THROW_A_NPE)) {
          verifyBarPass(method, bar); // only pass if 1st param throws NPE
        } else {
          verifyBarFail(method, bar);
        }
      }
    }
  }

  public void testTwoArgNullableNormal() throws Exception {

  private enum SupplierFunctionImpl implements SupplierFunction<@Nullable Object> {
    INSTANCE;

    // Note: This makes T a "pass-through type"
    @Override
    public @Nullable Object apply(Supplier<@Nullable Object> input) {
      return input.get();
    }

    @Override
    public String toString() {

       * all inputs for exceptions *if* we're collecting values. If we're not, then the listener
       * doesn't need access to the futures again, so we can just pass `null`.
       *
       * TODO(b/112550045): Allocating a single, cheaper listener is (I think) only an optimization.
       * If we make some other optimizations, this one will no longer be necessary. The optimization

## Context Managers { #context-managers }

### What are "Context Managers" { #what-are-context-managers }

     * 1) An interface I extending Comparable<I> so that the created array is of
     * an interface type. 2) An instance of a class implementing that interface
     * so that we can pass non-null instances of the interface.
     *
     * (Currently it's safe to pass instances for which compareTo() always
     * returns 0, but if we had a SingletonImmutableSortedSet, this might no
     * longer be the case.)
     *

        ProtwordsItem newItem = new ProtwordsItem(0, "testNew");
        ProtwordsFile.ProtwordsUpdater updater = protwordsFile.new ProtwordsUpdater(newItem);

        // Write an existing item (should pass through)
        ProtwordsItem existingItem = new ProtwordsItem(10, "existing");
        ProtwordsItem result = updater.write(existingItem);

        assertNotNull(result);