dependant: Dependant,
    body: Optional[Union[Dict[str, Any], FormData]] = None,
    background_tasks: Optional[StarletteBackgroundTasks] = None,
    response: Optional[Response] = None,
    dependency_overrides_provider: Optional[Any] = None,
    dependency_cache: Optional[Dict[Tuple[Callable[..., Any], Tuple[str]], Any]] = None,
    async_exit_stack: AsyncExitStack,
    embed_body_fields: bool,
) -> SolvedDependency:

        Doc(
            """
            'Whitelist' validation step. The parameter field will be the single one
            allowed by the alias or set of aliases defined.
            """
        ),
    ] = None,
    serialization_alias: Annotated[
        Union[str, None],
        Doc(
            """
            'Blacklist' validation step. The vanilla parameter field will be the

                """
            ),
        ] = None,
        scheme_name: Annotated[
            Optional[str],
            Doc(
                """
                Security scheme name.

                It will be included in the generated OpenAPI (e.g. visible at `/docs`).
                """
            ),
        ] = None,
        scopes: Annotated[

etween","inclusivity","localFrom","localTo","isSame","inputMs","isSameOrAfter","isSameOrBefore","parsingFlags","prioritized","unitsObj","u","getPrioritizedUnits","toArray","toObject","toDate","toISOString","keepOffset","inspect","prefix","suffix","zone","isLocal","Symbol","for","toJSON","unix","creationData","eraName","since","until","eraNarrow","eraAbbr","eraYear","dir","isoWeeks","weekInfo","weeksInWeekYear","isoWeeksInYear","isoWeeksInISOWeekYear","keepLocalTime","keepMinutes","localAdjust","...

                        newHashSet("a", elements[0], "b"), newHashSet("c", elements[0], "d"));
                  }
                })
            .named("intersection with overlap of one")
            .withFeatures(CollectionSize.ONE, CollectionFeature.ALLOWS_NULL_VALUES)
            .createTestSuite());

    suite.addTest(
        SetTestSuiteBuilder.using(
                new TestStringSetGenerator() {

                        newHashSet("a", elements[0], "b"), newHashSet("c", elements[0], "d"));
                  }
                })
            .named("intersection with overlap of one")
            .withFeatures(CollectionSize.ONE, CollectionFeature.ALLOWS_NULL_VALUES)
            .createTestSuite());

    suite.addTest(
        SetTestSuiteBuilder.using(
                new TestStringSetGenerator() {

```

/// tip

The second argument to <a href="https://docs.python.org/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> is the default value to return.

If not provided, it's `None` by default, here we provide `"World"` as the default value to use.

///

Then you could call that Python program:

//// tab | Linux, macOS, Windows Bash

<div class="termy">

```console

			}
			err = next(resp.Msg)
			if err != nil {
				s.cancel(err)
				return err
			}
		}
	}
}

// Done will return a channel that will be closed when the stream is done.
// This mirrors context.Done().
func (s *Stream) Done() <-chan struct{} {
	return s.ctx.Done()
}

// Err will return the error that caused the stream to end.
// This mirrors context.Err().
func (s *Stream) Err() error {

			return true
		}
	}

	// None found return false, perhaps entry removed in previous run.
	return false
}

func (l *localLocker) RLock(ctx context.Context, args dsync.LockArgs) (reply bool, err error) {
	if len(args.Resources) != 1 {
		return false, fmt.Errorf("internal error: localLocker.RLock called with more than one resource")
	}

	l.mutex.Lock()
	defer l.mutex.Unlock()

The way to describe this in OpenAPI, is to mark that field as **required**, because it will always be there.

Because of that, the JSON Schema for a model can be different depending on if it's used for **input or output**:

* for **input** the `description` will **not be required**
* for **output** it will be **required** (and possibly `None`, or in JSON terms, `null`)