* </pre>
   *
   * @throws IllegalArgumentException if there is a loop in the causal chain
   */
  public static Throwable getRootCause(Throwable throwable) {
    // Keep a second pointer that slowly walks the causal chain. If the fast pointer ever catches
    // the slower pointer, then there's a loop.
    Throwable slowPointer = throwable;

   * </pre>
   *
   * @throws IllegalArgumentException if there is a loop in the causal chain
   */
  public static Throwable getRootCause(Throwable throwable) {
    // Keep a second pointer that slowly walks the causal chain. If the fast pointer ever catches
    // the slower pointer, then there's a loop.
    Throwable slowPointer = throwable;

    firstException = expected;
    // Second time should also fail, with a cached causal chain.
    expected = assertThrows(PotentialDeadlockException.class, () -> lockA.lock());
    checkMessage(expected, "LockB -> LockA", "LockA -> LockB");
    // The causal chain should be cached.
    assertSame(firstException.getCause(), expected.getCause());
    // lockA should work after lockB is released.

    firstException = expected;
    // Second time should also fail, with a cached causal chain.
    expected = assertThrows(PotentialDeadlockException.class, () -> lockA.lock());
    checkMessage(expected, "LockB -> LockA", "LockA -> LockB");
    // The causal chain should be cached.
    assertSame(firstException.getCause(), expected.getCause());
    // lockA should work after lockB is released.

    # Do some sequential stuff to create the burgers
    return burgers
```

Con `async def`, Python sabe que, dentro de esa función, debe tener en cuenta las expresiones `wait` y que puede "pausar" ⏸ la ejecución de esa función e ir a hacer otra cosa 🔀 antes de regresar.

Cuando desees llamar a una función `async def`, debes "esperarla". Entonces, esto no funcionará:

```Python

      // The results of all other inputs are then ignored (except for logging any failures).
      boolean completedWithFailure = setException(throwable);
      if (!completedWithFailure) {
        // Go up the causal chain to see if we've already seen this cause; if we have, even if
        // it's wrapped by a different exception, don't log it.
        boolean firstTimeSeeingThisException = addCausalChain(getOrInitSeenExceptions(), throwable);

          setStackTrace(Arrays.copyOfRange(origStackTrace, i, n));
          break;
        }
      }
    }
  }

  /**
   * Represents a detected cycle in lock acquisition ordering. The exception includes a causal chain
   * of {@code ExampleStackTrace} instances to illustrate the cycle, e.g.
   *
   * <pre>
   * com....PotentialDeadlockException: Potential Deadlock from LockC -&gt; ReadWriteA
   *   at ...
   *   at ...

    # Faz alguma coisa sequencial para criar os hambúrgueres
    return burgers
```

Com `async def`, o Python sabe que, dentro dessa função, tem que estar ciente das expressões `await`, e que isso pode "pausar" a execução dessa função, e poderá fazer outra coisa antes de voltar.

Quando você quiser chamar uma função `async def`, você tem que "esperar". Então, isso não funcionará:

```Python

    !!! note
        `--no-cache-dir` é apenas relacionado ao `pip`, não tem nada a ver com Docker ou contêineres.

    A opção `--upgrade` diz ao `pip` para atualizar os pacotes se eles já estiverem instalados.

    Por causa do passo anterior de copiar o arquivo, ele pode ser detectado pelo **cache do Docker**, esse passo também **usará o cache do Docker** quando disponível.