Als je een recentere versie van Python kunt kiezen voor je project, kun je profiteren van die extra eenvoud.

In alle documentatie staan voorbeelden die compatibel zijn met elke versie van Python (als er een verschil is).

        assertEquals("true", returned.get("useKeyTab"));
        assertEquals("true", returned.get("storeKey"));
        assertEquals("******@****.***", returned.get("principal"));
        // Ensure no unexpected extra options
        assertEquals(3, returned.size(), "Only provided options are expected");
    }

    @Test

{* ../../docs_src/custom_request_and_route/tutorial003.py hl[26] *}

In this example, the *path operations* under the `router` will use the custom `TimedRoute` class, and will have an extra `X-Response-Time` header in the response with the time it took to generate the response:

And if you declared a `response_model`, it will still be used to filter and convert the object you returned.

**FastAPI** will use that *temporal* response to extract the status code (also cookies and headers), and will put them in the final response that contains the value you returned, filtered by any `response_model`.

E se você declarar um `response_model`, ele ainda será utilizado para filtrar e converter o objeto que você retornou.

O **FastAPI** utilizará este retorno *temporal* para extrair o código de status (e também cookies e headers), e irá colocá-los no retorno final que contém o valor que você retornou, filtrado por qualquer `response_model`.

      //
      // We use two volatile reads. We could reduce this to one by
      // putting our fields into a holder class, but (at least on x86)
      // the extra memory consumption and indirection are more
      // expensive than the extra volatile reads.
      long nanos = expirationNanos;
      long now = System.nanoTime();
      if (nanos == 0 || now - nanos >= 0) {
        synchronized (lock) {

FastAPI supports dependencies that do some <abbr title='sometimes also called "exit code", "cleanup code", "teardown code", "closing code", "context manager exit code", etc.'>extra steps after finishing</abbr>.

To do this, use `yield` instead of `return`, and write the extra steps (code) after.

/// tip

Make sure to use `yield` one single time per dependency.

///

/// note | Technical Details

                res.sendRedirect(locationBuf.toString());
                return;
            }
        }

        chain.doFilter(request, response);
    }

    /**
     * Extracts and parses parameters from the request query string.
     * Applies the specified character encoding to decode parameter values.
     *
     * @param request the HTTP request containing the query string

    void writeBytesWireFormat_writesExpectedValuesAtOffset(int offset) {
        // Arrange
        Smb2LogoffRequest req = newRequest();
        byte[] buf = new byte[offset + 8]; // extra space for safety

        // Act
        int written = req.writeBytesWireFormat(buf, offset);

        // Assert: should write exactly 4 bytes
        assertEquals(4, written, "Should report 4 bytes written");

Você pode utilizar as mesmas *funções* de dependências que você usaria normalmente.

### Requisitos de Dependências

Dependências podem declarar requisitos de requisições (como cabeçalhos) ou outras subdependências:

{* ../../docs_src/dependencies/tutorial006_an_py39.py hl[8,13] *}

### Levantando exceções

Essas dependências podem levantar exceções, da mesma forma que dependências comuns: