Isso é bastante simples (e não muito útil), mas irá nos ajudar a focar em como as subdependências funcionam.

## Segunda dependência, "injetável" e "dependente"

Então, você pode criar uma outra função para uma dependência (um "injetável") que ao mesmo tempo declara sua própria dependência (o que faz dela um "dependente" também):

{* ../../docs_src/dependencies/tutorial005_an_py310.py hl[13] *}

Vamos focar nos parâmetros declarados:

 *
 * @since 4.0.0
 */
@Experimental
@Immutable
public interface Dependency extends Artifact {
    /**
     * {@return the type of the dependency}.
     * A dependency can be a <abbr>JAR</abbr> file,
     * a modular-<abbr>JAR</abbr> if it is intended to be placed on the module path,
     * a <abbr>JAR</abbr> containing test classes, <i>etc.</i>

This is quite simple (not very useful), but will help us focus on how the sub-dependencies work.

## Second dependency, "dependable" and "dependant" { #second-dependency-dependable-and-dependant }

Then you can create another dependency function (a "dependable") that at the same time declares a dependency of its own (so it is a "dependant" too):

{* ../../docs_src/dependencies/tutorial005_an_py310.py hl[13] *}

Let's focus on the parameters declared:

## Zweite Abhängigkeit, „Dependable“ und „Dependant“

Dann können Sie eine weitere Abhängigkeitsfunktion (ein „Dependable“) erstellen, die gleichzeitig eine eigene Abhängigkeit deklariert (also auch ein „Dependant“ ist):

{* ../../docs_src/dependencies/tutorial005_an_py310.py hl[13] *}

Betrachten wir die deklarierten Parameter:

It is designed to be very simple to use, and to make it very easy for any developer to integrate other components with **FastAPI**.

## What is "Dependency Injection" { #what-is-dependency-injection }

 * Parses and evaluates version ranges encountered in dependency declarations.
 *
 * @since 4.0.0
 */
@Experimental
@Consumer
public interface VersionRangeResolver extends Service {

    /**
     * Expands a version range to a list of matching versions, in ascending order.
     * For example, resolves "[3.8,4.0)" to "3.8", "3.8.1", "3.8.2".
     * The returned list of versions is only dependent on the configured repositories and their contents.

Esto es bastante simple (no muy útil), pero nos ayudará a centrarnos en cómo funcionan las sub-dependencias.

## Segunda dependencia, "dependable" y "dependant"

Luego puedes crear otra función de dependencia (un "dependable") que al mismo tiempo declare una dependencia propia (por lo que también es un "dependant"):

{* ../../docs_src/dependencies/tutorial005_an_py310.py hl[13] *}

Centrémonos en los parámetros declarados:

     * the default is a Maven-specific variation of the {@code "glob"} pattern.
     *
     * <p>The default implementation returns an empty list, which means to apply a language-dependent pattern.
     * For example, for the Java language, the pattern includes all files with the {@code .java} suffix.</p>
     *
     * @see java.nio.file.FileSystem#getPathMatcher(String)
     */

        return create(DependencyCoordinatesFactoryRequest.build(session, dependency));
    }

    @Nonnull
    default DependencyCoordinates create(@Nonnull Session session, Dependency dependency) {
        return create(DependencyCoordinatesFactoryRequest.build(
                session,
                dependency.getGroupId(),
                dependency.getArtifactId(),

We can do better...

## What makes a dependency { #what-makes-a-dependency }

Up to now you have seen dependencies declared as functions.

But that's not the only way to declare dependencies (although it would probably be the more common).

The key factor is that a dependency should be a "callable".

A "**callable**" in Python is anything that Python can "call" like a function.