assertTrue(
        "addAll(somePresent) should return true",
        collection.addAll(MinimalCollection.of(e3(), e0())));
    assertTrue("should contain " + e3(), collection.contains(e3()));
    assertTrue("should contain " + e0(), collection.contains(e0()));
  }

  @CollectionFeature.Require(absent = SUPPORTS_ADD)
  @CollectionSize.Require(absent = ZERO)
  public void testAddAll_unsupportedSomePresent() {

      put(nullKeyEntry);
      fail("put(null, value) should throw");
    } catch (NullPointerException expected) {
    }
    expectUnchanged();
    expectNullKeyMissingWhenNullKeysUnsupported(
        "Should not contain null key after unsupported put(null, value)");
  }

  @MapFeature.Require({SUPPORTS_PUT, ALLOWS_NULL_VALUES})
  public void testPut_nullValueSupported() {

Let's say you have a *path operation* with a path `/files/{file_path}`.

But you need `file_path` itself to contain a *path*, like `home/johndoe/myfile.txt`.

So, the URL for that file would be something like: `/files/home/johndoe/myfile.txt`.

### OpenAPI support

OpenAPI doesn't support a way to declare a *path parameter* to contain a *path* inside, as that could lead to scenarios that are difficult to test and define.

		// Setting `prefix` to contain the object name as its prefix (Test number 23).
		{bucketNames[0], "min", "", "", "", 2, listMultipartResults[10], nil, true},
		// Setting `prefix` to contain the object name as its prefix (Test number 24).
		{bucketNames[0], "min", "", "", "", 1, listMultipartResults[11], nil, true},
		// Setting `prefix` to not to contain the object name as its prefix (Test number 25-26).

   * whose elements are the result of applying {@code elementFunction} to the inputs, with counts
   * equal to the result of applying {@code countFunction} to the inputs.
   *
   * <p>If the mapped elements contain duplicates (according to {@code comparator}), the first
   * occurrence in encounter order appears in the resulting multiset, with count equal to the sum of

          return optional.orNull();
        }
      };

  /**
   * Sets.cartesianProduct doesn't allow sets that contain null, but we want null to mean "don't
   * call the associated CacheBuilder method" - that is, get the default CacheBuilder behavior. This
   * method wraps the elements in the input sets (which may contain null) as Optionals, calls
   * Sets.cartesianProduct with those, then transforms the result to unwrap the Optionals.
   */

      put(nullKeyEntry);
      fail("put(null, value) should throw");
    } catch (NullPointerException expected) {
    }
    expectUnchanged();
    expectNullKeyMissingWhenNullKeysUnsupported(
        "Should not contain null key after unsupported put(null, value)");
  }

  @MapFeature.Require({SUPPORTS_PUT, ALLOWS_NULL_VALUES})
  public void testPut_nullValueSupported() {

## The normal **FastAPI** app

Let's first see how the normal API app would look like before adding the callback.

It will have a *path operation* that will receive an `Invoice` body, and a query parameter `callback_url` that will contain the URL for the callback.

This part is pretty normal, most of the code is probably already familiar to you:

```Python hl_lines="9-13  36-53"
{!../../../docs_src/openapi_callbacks/tutorial001.py!}
```

!!! tip

  // stomped by the controller.
  // +optional
  optional AggregationRule aggregationRule = 3;
}

// ClusterRoleBinding references a ClusterRole, but not contain it.  It can reference a ClusterRole in the global namespace,
// and adds who information via Subject.
// Deprecated in v1.17 in favor of rbac.authorization.k8s.io/v1 ClusterRoleBinding, and will no longer be served in v1.22.

  // stomped by the controller.
  // +optional
  optional AggregationRule aggregationRule = 3;
}

// ClusterRoleBinding references a ClusterRole, but not contain it.  It can reference a ClusterRole in the global namespace,
// and adds who information via Subject.
// Deprecated in v1.17 in favor of rbac.authorization.k8s.io/v1 ClusterRoleBinding, and will no longer be served in v1.22.