is not available, instead of erroring out, the dependency result will
                be `None`.

                This is useful when you want to have optional authentication.

                It is also useful when you want to have authentication that can be
                provided in one of multiple optional ways (for example, with OAuth2
                or in a cookie).
                """
            ),

## Another module with `APIRouter`

Let's say you also have the endpoints dedicated to handling "items" from your application in the module at `app/routers/items.py`.

You have *path operations* for:

* `/items/`
* `/items/{item_id}`

It's all the same structure as with `app/routers/users.py`.

* Maven test harness for plugin execution model
* Eclipse IDE tooling for plugin execution model and metadata model

- we also seem to have information like the plugin lifecycle model that's buried inside the maven execution model
- we also seem to have artifact information tangled inside the plugin model
- we have to deal with scripting implementations (groovy, beanshell, ruby)
- we need to deal with a shared context for plugins, like the guarded mojos

  // Views

  /**
   * Returns a view of all mappings that have the given row key. For each row key / column key /
   * value mapping in the table with that row key, the returned map associates the column key with
   * the value. If no mappings in the table have the provided row key, an empty map is returned.
   *

   * we're guaranteed to have properly initialized the subclass.
   */
  final void init() {
    /*
     * requireNonNull is safe because this is called from the constructor after `futures` is set but
     * before releaseResources could be called (because we have not yet set up any of the listeners

     *
     * <p>This will be called at most once after all the services have entered the {@linkplain
     * State#RUNNING running} state. If any services fail during start up or {@linkplain
     * State#FAILED fail}/{@linkplain State#TERMINATED terminate} before all other services have
     * started {@linkplain State#RUNNING running} then this method will not be called.
     */

   * filters to be compatible, they must:
   *
   * <ul>
   *   <li>not be the same instance
   *   <li>have the same number of hash functions
   *   <li>have the same bit size
   *   <li>have the same strategy
   *   <li>have equal funnels
   * </ul>
   *
   * @param that The Bloom filter to check for compatibility.
   * @since 15.0
   */

    {!> ../../../docs_src/dependencies/tutorial008.py!}
    ```

The same way, you could have some dependencies with `yield` and some other dependencies with `return`, and have some of those depend on some of the others.

And you could have a single dependency that requires several other dependencies with `yield`, etc.

You can have any combinations of dependencies that you want.

Then you could want to have **a single container** with a **process manager** starting **several worker processes** inside.

#### Prometheus and Other Reasons

   |
   | It works like this: a POM may declare a repository to use in resolving certain artifacts.
   | However, this repository may have problems with heavy traffic at times, so people have mirrored
   | it to several places.
   |
   | That repository definition will have a unique id, so we can create a mirror reference for that
   | repository, to be used as an alternate download site. The mirror site will be the preferred