FastAPI does several things internally with Pydantic to make sure that those same rules of class inheritance are not used for the returned data filtering, otherwise you could end up returning much more data than what you expected.

This way, you can get the best of both worlds: type annotations with **tooling support** and **data filtering**.

## See it in the docs { #see-it-in-the-docs }

First of all, be nice. 😊

You probably are super nice if you were added to the team, but it's worth mentioning it. 🤓

### When Things are Difficult

When things are great, everything is easier, so that doesn't need much instructions. But when things are difficult, here are some guidelines.

   * ```
   *
   * But this chain is wrong because the attackerSwitch certificate is being used in a CA role even
   * though it is not a CA certificate. There are pinned certificates in the chain! The correct
   * chain is much shorter because it skips the non-CA certificate.
   *
   * ```
   *   attackerCa
   *     -> attackerIntermediate
   *         -> phonyVictim
   * ```
   *

    assertThrows(IndexOutOfBoundsException.class, () -> iia3.subArray(1, 4));
  }

  /*
   * Whenever an implementation uses `instanceof` on a parameter instance, the test has to know that
   * (so much for "black box") and try instances that both do and don't pass the check. The "don't"
   * half of that is more awkward to arrange...
   */
  private static <T> Iterable<T> iterable(Collection<T> collection) {

  <artifactId>guava-gwt</artifactId>
  <name>Guava GWT compatible libs</name>
  <description>
    Guava is a suite of core and expanded libraries that include
    utility classes, Google's collections, I/O classes, and
    much more.

    This project includes GWT-friendly sources.
  </description>
  <properties>
    <gwt.version>2.12.2</gwt.version>
    <gwt.plugin.version>2.10.0</gwt.plugin.version>
    <gwt.logLevel>WARN</gwt.logLevel>

   *
   * <p><i>Performance notes:</i> while the cartesian product of lists of size {@code m, n, p} is a
   * list of size {@code m x n x p}, its actual memory consumption is much smaller. When the
   * cartesian product is constructed, the input lists are merely copied. Only as the resulting list
   * is iterated are the individual lists created, and these are not retained after iteration.
   *

```Python hl_lines="1"
async def get_burgers(number: int):
    # Mach Sie hier etwas Asynchrones, um die Burger zu erstellen
    return burgers
```

... statt mit `def`:

```Python hl_lines="2"
# Die ist nicht asynchron
def get_sequential_burgers(number: int):
    # Mach Sie hier etwas Sequentielles, um die Burger zu erstellen
    return burgers
```

    assertThat((long) arraysDim1 * arraysDim2).isNotEqualTo((long) (arraysDim1 * arraysDim2));

    char[][] arrays = new char[arraysDim1][];
    // it's shared to avoid using too much memory in tests
    char[] sharedArray = new char[arraysDim2];
    Arrays.fill(arrays, sharedArray);

    try {
      Chars.concat(arrays);
      fail();
    } catch (IllegalArgumentException expected) {

Auf der anderen Seite gibt es Tausende von Benutzern in den Chat-Systemen, sodass die Wahrscheinlichkeit hoch ist, dass Sie dort fast immer jemanden zum Reden finden. 😄

## Den Autor sponsern

Sie können den Autor (mich) auch über <a href="https://github.com/sponsors/tiangolo" class="external-link" target="_blank">GitHub-Sponsoren</a> finanziell unterstützen.

Dort könnten Sie mir als Dankeschön einen Kaffee spendieren ☕️. 😄

   * higher value than you need can waste space and time, and a significantly lower value can lead
   * to thread contention. But overestimates and underestimates within an order of magnitude do not
   * usually have much noticeable impact. A value of one permits only one thread to modify the cache
   * at a time, but since read operations and cache loading computations can proceed concurrently,