# Sub-dependencias

Puedes crear dependencias que tengan **sub-dependencias**.

Pueden ser tan **profundas** como necesites.

**FastAPI** se encargará de resolverlas.

## Primera dependencia "dependable"

Podrías crear una primera dependencia ("dependable") así:

{* ../../docs_src/dependencies/tutorial005_an_py310.py hl[8:9] *}

Declara un parámetro de query opcional `q` como un `str`, y luego simplemente lo devuelve.

          <type>String</type>
        </field>
        <field>
          <name>distribution</name>
          <version>3.0.0+</version>
          <description>
            <![CDATA[
            The primary method by which this project may be distributed.
            <dl>
              <dt>repo</dt>
              <dd>may be downloaded from the Maven repository</dd>
              <dt>manual</dt>

- Added dynamic audit configuration api ([#67547](https://github.com/kubernetes/kubernetes/pull/67547), [@pbarker](https://github.com/pbarker))
- Added ability to control primary GID of containers through Pod Spec and PodSecurityPolicy ([#67802](https://github.com/kubernetes/kubernetes/pull/67802), [@krmayankk](https://github.com/krmayankk))

h","handler","special","that","mightThrow","TypeError","notifyWith","resolveWith","process","exceptionHook","rejectWith","getErrorHook","getStackHook","setTimeout","stateString","when","singleValue","remaining","resolveContexts","resolveValues","primary","updateFunc","rerrorNames","asyncError","console","warn","message","stack","readyException","readyList","completed","removeEventListener","readyWait","wait","readyState","doScroll","access","chainable","emptyGet","raw","bulk","_key","rmsPrefix",...

Entonces el código de Python en tu aplicación equivaldría a algo como:

```Python
if "johndoe" == "stanleyjobson" and "love123" == "swordfish":
    ...
```

- [Dual-stack] Fixed `generateAPIPodStatus()` of kubelet handling Secondary IP. hostIPs order may not be consistent. If secondary IP is before primary one, current logic adds primary IP twice into `PodIPs`, which leads to error: "may specify no more than one IP for each IP family". ([#116879](https://github.com/kubernetes/kubernetes/pull/116879), [@lzhecheng](https://github.com/lzhecheng))

* Add support for terminal resizing for exec, attach, and run. Note that for Docker, exec sessions ([#25273](https://github.com/kubernetes/kubernetes/pull/25273), [@ncdc](https://github.com/ncdc))
    * inherit the environment from the primary process, so if the container was created with tty=false,that means the exec session's TERM variable will default to "dumb". Users can override this by setting TERM=xterm (or whatever is appropriate) to get the correct "smart" terminal behavior.

De la misma manera que puedes declarar más validaciones y metadatos para los parámetros de query con `Query`, puedes declarar el mismo tipo de validaciones y metadatos para los parámetros de path con `Path`.

## Importar Path

Primero, importa `Path` de `fastapi`, e importa `Annotated`:

{* ../../docs_src/path_params_numeric_validations/tutorial001_an_py310.py hl[1,3] *}

/// info | Información

```console
// Aquí todavía no configuramos la env var
$ python main.py

// Como no configuramos la env var, obtenemos el valor por defecto

Hello World from Python

// Pero si creamos una variable de entorno primero
$ export MY_NAME="Wade Wilson"

// Y luego llamamos al programa nuevamente
$ python main.py

// Ahora puede leer la variable de entorno

Hello Wade Wilson from Python
```

</div>

////

La **Guía Avanzada del Usuario** se basa en esta, utiliza los mismos conceptos y te enseña algunas funcionalidades adicionales.

Pero primero deberías leer la **Tutorial - Guía del Usuario** (lo que estás leyendo ahora mismo).