!!! note
    FastAPI will know that the value of `q` is not required because of the default value `= None`.

    The `Union` in `Union[str, None]` is not used by FastAPI, but will allow your editor to give you better support and detect errors.

## Without Pydantic

                This is much simpler (less smart) than `response_model_exclude_unset`
                and `response_model_exclude_defaults`. You probably want to use one of
                those two instead of this one, as those allow returning `None` values
                when it makes sense.

                Read more about it in the

                exclude_defaults=exclude_defaults,
                exclude_none=exclude_none,
            )

        def __hash__(self) -> int:
            # Each ModelField is unique for our purposes, to allow making a dict from
            # ModelField to its JSON Schema.
            return id(self)

    def get_annotation_from_field_info(
        annotation: Any, field_info: FieldInfo, field_name: str
    ) -> Any:

### One Load Balancer - Multiple Worker Containers

When working with **Kubernetes** or similar distributed container management systems, using their internal networking mechanisms would allow the single **load balancer** that is listening on the main **port** to transmit communication (requests) to possibly **multiple containers** running your app.