Callable<T> callable, ListeningExecutorService listeningExecutorService) {
    checkNotNull(callable);
    checkNotNull(listeningExecutorService);
    return () -> listeningExecutorService.submit(callable);
  }

  /**
   * Wraps the given callable such that for the duration of {@link Callable#call} the thread that is
   * running will have the given name.
   *
   * @param callable The callable to wrap

  public void testReturning() throws Exception {
    assertThat(Callables.returning(null).call()).isNull();

    Object value = new Object();
    Callable<Object> callable = Callables.returning(value);
    assertThat(callable.call()).isEqualTo(value);
    // Expect the same value on subsequent calls
    assertThat(callable.call()).isEqualTo(value);
  }

  @J2ktIncompatible
  @GwtIncompatible

  public void testReturning() throws Exception {
    assertThat(Callables.returning(null).call()).isNull();

    Object value = new Object();
    Callable<Object> callable = Callables.returning(value);
    assertThat(callable.call()).isEqualTo(value);
    // Expect the same value on subsequent calls
    assertThat(callable.call()).isEqualTo(value);
  }

  @J2ktIncompatible
  @GwtIncompatible

So, a Python class is also a **callable**.

Then, in **FastAPI**, you could use a Python class as a dependency.

What FastAPI actually checks is that it is a "callable" (function, class or anything else) and the parameters defined.

    super.setUp();
    timeLimiter = new FakeTimeLimiter();
  }

  public void testCallWithTimeout_propagatesReturnValue() throws Exception {
    String result =
        timeLimiter.callWithTimeout(Callables.returning(RETURN_VALUE), DELAY_MS, MILLISECONDS);

    assertThat(result).isEqualTo(RETURN_VALUE);
  }

  public void testCallWithTimeout_wrapsCheckedException() throws Exception {

    super.setUp();
    timeLimiter = new FakeTimeLimiter();
  }

  public void testCallWithTimeout_propagatesReturnValue() throws Exception {
    String result =
        timeLimiter.callWithTimeout(Callables.returning(RETURN_VALUE), DELAY_MS, MILLISECONDS);

    assertThat(result).isEqualTo(RETURN_VALUE);
  }

  public void testCallWithTimeout_wrapsCheckedException() throws Exception {

Eine Python-Klasse ist also auch ein **Callable**.

Darum können Sie in **FastAPI** auch eine Python-Klasse als Abhängigkeit verwenden.

Was FastAPI tatsächlich prüft, ist, ob es sich um ein „Callable“ (Funktion, Klasse oder irgendetwas anderes) handelt und ob die Parameter definiert sind.

 * limitations under the License.
 */

package com.google.common.util.concurrent;

import static com.google.common.truth.Truth.assertThat;
import static com.google.common.util.concurrent.Callables.returning;
import static com.google.common.util.concurrent.Futures.getDone;
import static com.google.common.util.concurrent.Futures.immediateFuture;

 * limitations under the License.
 */

package com.google.common.util.concurrent;

import static com.google.common.truth.Truth.assertThat;
import static com.google.common.util.concurrent.Callables.returning;
import static com.google.common.util.concurrent.Futures.getDone;
import static com.google.common.util.concurrent.Futures.immediateFuture;

Et pour créer `fluffy`, vous « appelez » `Cat`.

Donc, une classe Python est aussi un « callable ».

Ainsi, avec **FastAPI**, vous pouvez utiliser une classe Python comme dépendance.

Ce que **FastAPI** vérifie réellement, c'est qu'il s'agit d'un « callable » (fonction, classe ou autre) et des paramètres qui y sont définis.