public void testRemoveAtIndexConcurrentWithIteration() {
    assertThrows(
        ConcurrentModificationException.class,
        () -> {
          Iterator<E> iterator = collection.iterator();
          getList().remove(getNumElements() / 2);
          iterator.next();
        });
  }

  @ListFeature.Require(SUPPORTS_REMOVE_WITH_INDEX)
  @CollectionSize.Require(absent = ZERO)
  public void testRemoveAtIndex_last() {

    assert response.json()["message"] == "Successful operation."


def test_response_model_has_default_factory_return_model():
    response = client.get("/response_model_has_default_factory_return_model")

    assert response.status_code == 200, response.text

    assert response.json()["code"] == 200

* It takes each **request** that comes to your application.
* It can then do something to that **request** or run any needed code.
* Then it passes the **request** to be processed by the rest of the application (by some *path operation*).

{* ../../docs_src/security/tutorial002_an_py310.py hl[30:32] *}

## Recap { #recap }

You can now get the current user directly in your *path operation function*.

We are already halfway there.

We just need to add a *path operation* for the user/client to actually send the `username` and `password`.

          @Override
          public Iterator<Entry<Range<K>, V>> iterator() {
            return entryIterator();
          }

          @Override
          public boolean retainAll(Collection<?> c) {
            return removeEntryIf(not(in(c)));
          }

          @Override
          public int size() {
            return Iterators.size(iterator());
          }

          @Override

{* ../../docs_src/security/tutorial002_an_py310.py hl[30:32] *}

## Resumen { #recap }

Ahora puedes obtener el usuario actual directamente en tu *path operation function*.

Ya estamos a mitad de camino.

Solo necesitamos agregar una *path operation* para que el usuario/cliente envíe realmente el `username` y `password`.

    end
    dep ->> operation: Führt Abhängigkeit aus, z. B. DB-Session
    opt Löst aus
        operation -->> dep: Löst Exception aus (z. B. HTTPException)
        opt Handhabt
            dep -->> dep: Kann Exception abfangen, eine neue HTTPException auslösen, andere Exception auslösen
        end
        handler -->> client: HTTP-Error-Response
    end

    operation ->> client: Sendet Response an Client

  ) = throw CertificateException("Unsupported operation")

  override fun checkClientTrusted(
    chain: Array<out X509Certificate>,
    authType: String?,
  ) = throw CertificateException("Unsupported operation")

  override fun checkClientTrusted(
    chain: Array<out X509Certificate>,
    authType: String,
    engine: SSLEngine?,
  ) = throw CertificateException("Unsupported operation")

  override fun checkClientTrusted(

  public SampleElements(E e0, E e1, E e2, E e3, E e4) {
    this.e0 = e0;
    this.e1 = e1;
    this.e2 = e2;
    this.e3 = e3;
    this.e4 = e4;
  }

  @Override
  public Iterator<E> iterator() {
    return asList().iterator();
  }

  public List<E> asList() {
    return Arrays.asList(e0(), e1(), e2(), e3(), e4());
  }

  public static class Strings extends SampleElements<String> {
    public Strings() {

    TreeMultimap<@Nullable String, @Nullable Integer> multimap = createPopulate();
    Iterator<Entry<String, Collection<Integer>>> iterator = multimap.asMap().entrySet().iterator();
    Entry<String, Collection<Integer>> entry = iterator.next();
    assertEquals(null, entry.getKey());
    assertThat(entry.getValue()).containsExactly(7, 3, 1);
    entry = iterator.next();
    assertEquals("tree", entry.getKey());