*
 * <p>For details about this hack, see {@code GwtSerializationDependencies}, which takes the same
 * approach but with a subclass rather than a superclass.
 *
 * <p>TODO(cpovirk): Consider applying this subclass approach to our other types.
 */
@GwtCompatible(emulated = true)
abstract class HashMultimapGwtSerializationDependencies<K, V> extends AbstractSetMultimap<K, V> {

 *
 * <p>For details about this hack, see {@code GwtSerializationDependencies}, which takes the same
 * approach but with a subclass rather than a superclass.
 *
 * <p>TODO(cpovirk): Consider applying this subclass approach to our other types.
 */
@GwtCompatible(emulated = true)
abstract class ArrayListMultimapGwtSerializationDependencies<K, V>
    extends AbstractListMultimap<K, V> {

        // The raw class isn't even a subclass.
      }
    }
    if (!spec.suppressGetSupertype()) {
      try {
        assertThat(getSupertype(paramType, TypeToken.of(returnType).getRawType()))
            .isNotEqualTo(returnType);
      } catch (IllegalArgumentException notSubtype2) {
        // The raw class isn't even a subclass.
      }
    }
    return null;
  }

        // The raw class isn't even a subclass.
      }
    }
    if (!spec.suppressGetSupertype()) {
      try {
        assertThat(getSupertype(paramType, TypeToken.of(returnType).getRawType()))
            .isNotEqualTo(returnType);
      } catch (IllegalArgumentException notSubtype2) {
        // The raw class isn't even a subclass.
      }
    }
    return null;
  }

 * subclasses. Without such overrides, optimizers might put a {@code writeReplace}-containing class
 * and its subclass in different packages, causing the serialization system to fail to invoke {@code
 * writeReplace} when serializing an instance of the subclass. For an example of this problem, see
 * b/310253115.
 */
public class WriteReplaceOverridesTest extends TestCase {

 *
 * <p>For details about this hack, see {@code GwtSerializationDependencies}, which takes the same
 * approach but with a subclass rather than a superclass.
 *
 * <p>TODO(cpovirk): Consider applying this subclass approach to our other types.
 */
@GwtCompatible(emulated = true)
abstract class LinkedHashMultimapGwtSerializationDependencies<K, V>
    extends AbstractSetMultimap<K, V> {

 *
 * <p>For details about this hack, see {@code GwtSerializationDependencies}, which takes the same
 * approach but with a subclass rather than a superclass.
 *
 * <p>TODO(cpovirk): Consider applying this subclass approach to our other types.
 */
@SuppressWarnings("rawtypes") // https://github.com/google/guava/issues/989
@GwtCompatible(emulated = true)

This simple case is handled automatically by FastAPI because the return type annotation is the class (or a subclass of) `Response`.

And tools will also be happy because both `RedirectResponse` and `JSONResponse` are subclasses of `Response`, so the type annotation is correct.

### Annotate a Response Subclass

You can also use a subclass of `Response` in the type annotation:

```Python hl_lines="8-9"

 * interface-specific subclass of {@code ForwardingObject}, such as {@link ForwardingList}, to
 * preserve equality behavior, or override {@code equals} directly.
 *
 * <p>The {@code toString} method is forwarded to the delegate. Although this class does not
 * implement {@link Serializable}, a serializable subclass may be created since this class has a
 * parameter-less constructor.
 *

              public void remove() {
                throw new IllegalStateException() {
                  /* subclass */
                };
              }

              @Override
              public Integer next() {
                throw new NoSuchElementException() {
                  /* subclass */
                };
              }

              @Override
              public boolean hasNext() {