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

#### Prometheus and Other Reasons

                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, in a query
                parameter or in an HTTP Bearer token).
                """

## 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`.

			return entries, io.EOF
		}
	}

	// With max keys of zero we have reached eof, return right here.
	if o.Limit == 0 {
		return entries, io.EOF
	}

	// For delimiter and prefix as '/' we do not list anything at all
	// along // with the prefix. On a flat namespace with 'prefix'
	// as '/' we don't have any entries, since all the keys are
	// of form 'keyName/...'

For example an object `orion_cat` (an instance of `Pet`) could have an attribute `orion_cat.type`, for the column `type`. And the value of that attribute could be, e.g. `"cat"`.

These ORMs also have tools to make the connections or relations between tables or entities.

This way, you could also have an attribute `orion_cat.owner` and the owner would contain the data for this pet's owner, taken from the table *owners*.

In this case, you could want to document how that external API *should* look like. What *path operation* it should have, what body it should expect, what response it should return, etc.

## An app with callbacks

Let's see all this with an example.

Imagine you develop an app that allows creating invoices.

These invoices will have an `id`, `title` (optional), `customer`, and `total`.

Using these ideas, JWT can be used for way more sophisticated scenarios.

In those cases, several of those entities could have the same ID, let's say `foo` (a user `foo`, a car `foo`, and a blog post `foo`).

    But `OAuth2PasswordRequestForm` is just a class dependency that you could have written yourself, or you could have declared `Form` parameters directly.

    But as it's a common use case, it is provided by **FastAPI** directly, just to make it easier.

### Use the form data

!!! tip

   * 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
   */

            continue@eachQueue
          }

          // If we already have more than one task, that's enough work for now. Stop searching.
          readyTask != null -> {
            multipleReadyTasks = true
            break@eachQueue
          }

          // We have a task to execute when we complete the loop.
          else -> {
            readyTask = candidate
          }