You can set the *path operation decorator* parameter `response_model_exclude_unset=True`:

{* ../../docs_src/response_model/tutorial004_py310.py hl[22] *}

and those default values won't be included in the response, only the values actually set.

So, if you send a request to that *path operation* for the item with ID `foo`, the response (not including default values) will be:

package com.google.common.collect.testing;

import com.google.common.annotations.GwtCompatible;
import java.util.Iterator;

/**
 * Creates iterators to be tested.
 *
 * @param <E> the element type of the iterator.
 * @author George van den Driessche
 */
@GwtCompatible
public interface TestIteratorGenerator<E> {
  Iterator<E> get();

        // Act: create iterator and enumerate
        DirFileEntryEnumIterator2 it = new DirFileEntryEnumIterator2(tree, parent, wildcard, (ResourceNameFilter) null, 0);

        // Assert: first page
        assertTrue(it.hasNext(), "Iterator should have first element");
        assertSame(fe1, it.next(), "First element must match first page");
        assertTrue(it.hasNext(), "Iterator should have second element");

    }

    void setValue(@ParametricNullness V value) {
      checkState(current != null);
      current.setValue(value);
    }
  }

  /** An {@code Iterator} over distinct keys in key head order. */
  private final class DistinctKeyIterator implements Iterator<K> {
    final Set<K> seenKeys = Sets.<K>newHashSetWithExpectedSize(keySet().size());
    @Nullable Node<K, V> next = head;
    @Nullable Node<K, V> current;

  }

  @Override
  public TestSubjectGenerator<? extends Iterable<E>> getInnerGenerator() {
    return collectionGenerator;
  }

  @Override
  public Iterator<E> get() {
    return collectionGenerator.createTestSubject().iterator();
  }

Pero también puedes declarar el `Response` que quieres usar (por ejemplo, cualquier subclase de `Response`), en el *path operation decorator* usando el parámetro `response_class`.

Los contenidos que devuelvas desde tu *path operation function* se colocarán dentro de esa `Response`.

...le "path" serait :

```
/items/foo
```

/// info

Un chemin, ou "path" est aussi souvent appelé route ou "endpoint".

///

#### Opération

"Opération" fait référence à une des "méthodes" HTTP.

Une de :

* `POST`
* `GET`
* `PUT`
* `DELETE`

...ou une des plus exotiques :

* `OPTIONS`
* `HEAD`
* `PATCH`
* `TRACE`

  public void testRemoveAllSomePresentConcurrentWithIteration() {
    assertThrows(
        ConcurrentModificationException.class,
        () -> {
          Iterator<E> iterator = collection.iterator();
          assertTrue(collection.removeAll(MinimalCollection.of(e0(), e3())));
          iterator.next();
        });
  }

  /** Trigger the {@code other.size() >= this.size()} case in {@link AbstractSet#removeAll}. */

      // the operation would be a no-op, so exceptions are allowed but not required
    }
    expectUnchanged();
  }

  @MapFeature.Require(absent = SUPPORTS_PUT)
  public void testReplaceEntry_unsupportedAbsentKey() {
    try {
      getMap().replace(k3(), v3(), v4());
    } catch (UnsupportedOperationException tolerated) {

    }

    @Override
    public SortedMultiset<E> descendingMultiset() {
      return new StandardDescendingMultiset() {

        @Override
        Iterator<Entry<E>> entryIterator() {
          return backingMultiset.descendingMultiset().entrySet().iterator();
        }
      };
    }

    @Override
    public NavigableSet<E> elementSet() {
      return new StandardElementSet();
    }

    @Override