* **GraphQL** integratie met <a href="https://strawberry.rocks" class="external-link" target="_blank">Strawberry</a> en andere packages.
* Veel extra functies (dankzij Starlette) zoals:
    * **WebSockets**
    * uiterst gemakkelijke tests gebaseerd op HTTPX en `pytest`
    * **CORS**
    * **Cookie Sessions**
    * ...en meer.

## Prestaties

   * typically by writing {@code (Function<Object, String> & Serializable) Object::toString}.
   *
   * <p>For more important information about the transition from Guava's {@link Function} class to
   * the JDK {@link java.util.function.Function} class, see {@link Function}.
   */
  public static Function<Object, String> toStringFunction() {
    return ToStringFunction.INSTANCE;
  }

    Function<? super Integer, Boolean> h = Functions.constant(Boolean.TRUE);
    Function<? super String, Integer> g = new HashCodeFunction();
    Function<Float, String> f = Functions.forMap(m, "F");

    Function<Float, Boolean> c1 = Functions.compose(Functions.compose(h, g), f);
    Function<Float, Boolean> c2 = Functions.compose(h, Functions.compose(g, f));

## pytest.mark.anyio { #pytest-mark-anyio }

If we want to call asynchronous functions in our tests, our test functions have to be asynchronous. AnyIO provides a neat plugin for this, that allows us to specify that some test functions are to be called asynchronously.

## HTTPX { #httpx }

Even if your **FastAPI** application uses normal `def` functions instead of `async def`, it is still an `async` application underneath.

    Function<? super Integer, Boolean> h = Functions.constant(Boolean.TRUE);
    Function<? super String, Integer> g = new HashCodeFunction();
    Function<Float, String> f = Functions.forMap(m, "F");

    Function<Float, Boolean> c1 = Functions.compose(Functions.compose(h, g), f);
    Function<Float, Boolean> c2 = Functions.compose(h, Functions.compose(g, f));

Let's first focus on the dependency.

It is just a function that can take all the same parameters that a *path operation function* can take:

{* ../../docs_src/dependencies/tutorial001_an_py310.py hl[8:9] *}

That's it.

**2 lines**.

And it has the same shape and structure that all your *path operation functions* have.

You can think of it as a *path operation function* without the "decorator" (without the `@app.get("/some-path")`).

### Other utility functions { #other-utility-functions }

Any other utility function that you call directly can be created with normal `def` or `async def` and FastAPI won't affect the way you call it.

This is in contrast to the functions that FastAPI calls for you: *path operation functions* and dependencies.

   *
   * @param function A Function to transform the results of this future to the results of the
   *     returned future.
   * @param executor Executor to run the function in.
   * @return A future that holds result of the transformation.
   */
  public final <T extends @Nullable Object> FluentFuture<T> transform(
      Function<? super V, T> function, Executor executor) {

    checkArgument(!list.isEmpty(), "number of hash functions (%s) must be > 0", list.size());
    return new ConcatenatedHashFunction(list.toArray(new HashFunction[0]));
  }

  private static final class ConcatenatedHashFunction extends AbstractCompositeHashFunction {

    private ConcatenatedHashFunction(HashFunction... functions) {
      super(functions);
      for (HashFunction function : functions) {
        checkArgument(

    new EqualsTester()
        .addEqualityGroup(
            Suppliers.compose(Functions.constant(1), Suppliers.ofInstance("foo")),
            Suppliers.compose(Functions.constant(1), Suppliers.ofInstance("foo")))
        .addEqualityGroup(Suppliers.compose(Functions.constant(2), Suppliers.ofInstance("foo")))
        .addEqualityGroup(Suppliers.compose(Functions.constant(1), Suppliers.ofInstance("bar")))
        .testEquals();
  }