* Swagger UI.
    * ReDoc.

---

Volviendo al ejemplo de código anterior, **FastAPI**:

* Validará que haya un `item_id` en el path para requests `GET` y `PUT`.
* Validará que el `item_id` sea del tipo `int` para requests `GET` y `PUT`.
    * Si no lo es, el cliente verá un error útil y claro.

   *
   * This same problem is one of the reasons for us to likewise use package-private for the fields
   * in Waiter.
   */

  /**
   * This field encodes the current state of the future.
   *
   * <p>The valid values are:
   *
   * <ul>
   *   <li>{@code null} initial state, nothing has happened.
   *   <li>{@link Cancellation} terminal state, {@code cancel} was called.

    state.addListener(listener, executor);
  }

  /**
   * Initiates service {@linkplain Service#startAsync startup} on all the services being managed. It
   * is only valid to call this method if all of the services are {@linkplain State#NEW new}.
   *
   * @return this
   * @throws IllegalStateException if any of the Services are not {@link State#NEW new} when the
   *     method is called.

        assertTrue(attributes >= 0, "Attributes should be valid");
    }

    @Test
    void testSetTimestamps() throws Exception {
        SmbFile file = new SmbFile(baseUrl + "shared/timestamps.txt", context);
        file.createNewFile();

        long originalTime = file.lastModified();
        assertTrue(originalTime > 0, "File should have a valid timestamp");

        // Test setting timestamp 1 hour ago

	vectors := []struct {
		input string // Input stream
		cnt   int    // Expected number of headers read
		err   error  // Expected error outcome
	}{
		{"", 0, io.EOF}, // Empty file is a "valid" tar file
		{data1[:511], 0, io.ErrUnexpectedEOF},
		{data1[:512], 1, io.ErrUnexpectedEOF},
		{data1[:1024], 1, io.EOF},
		{data1[:1536], 2, io.ErrUnexpectedEOF},
		{data1[:2048], 2, io.EOF},
		{data1, 2, io.EOF},

// This will make the branch rebalance itself when scanned if the distribution of objects has changed.

// scanDataFolder will scanner the basepath+cache.Info.Name and return an updated cache.
// The returned cache will always be valid, but may not be updated from the existing.
// Before each operation sleepDuration is called which can be used to temporarily halt the scanner.
// If the supplied context is canceled the function will return at the first chance.

```

The `name` parameter is **still required** (not *optional*) because it doesn't have a default value. Still, `name` accepts `None` as the value:

```Python
say_hi(name=None)  # This works, None is valid 🎉
```

The good news is, once you are on Python 3.10 you won't have to worry about that, as you will be able to simply use `|` to define unions of types:

{* ../../docs_src/python_types/tutorial009c_py310.py hl[1,4] *}

    // other operations, the cache and the removal queue won't change from this point on.

    // Verify that each received removal notification was valid
    for (RemovalNotification<String, String> notification : removalListener) {
      assertEquals("Invalid removal notification", notification.getKey(), notification.getValue());
    }

    // other operations, the cache and the removal queue won't change from this point on.

    // Verify that each received removal notification was valid
    for (RemovalNotification<String, String> notification : removalListener) {
      assertEquals("Invalid removal notification", notification.getKey(), notification.getValue());
    }

    // These contain bytes not in the decodabet.
    assertFailsToDecode(base16(), "\n\n", "Unrecognized character: 0xa");
    assertFailsToDecode(base16(), "EFGH", "Unrecognized character: G");
    // Valid base16 strings always have an even length.
    assertFailsToDecode(base16(), "A", "Invalid input length 1");
    assertFailsToDecode(base16(), "ABC");
    // These have a combination of invalid length and unrecognized characters.