Wenn wir ein `dict` wie `user_dict` nehmen, und es einer Funktion (oder Klassenmethode) mittels `**user_dict` übergeben, wird Python es „entpacken“. Es wird die Schlüssel und Werte von `user_dict` direkt als Schlüsselwort-Argumente übergeben.

Wenn wir also das `user_dict` von oben nehmen und schreiben:

```Python
UserInDB(**user_dict)
```

dann ist das ungefähr äquivalent zu:

```Python
UserInDB(
    username="john",

This schema definition includes your API paths, the possible parameters they take, etc.

#### Data "schema"

The term "schema" might also refer to the shape of some data, like a JSON content.

In that case, it would mean the JSON attributes, and data types they have, etc.

#### OpenAPI and JSON Schema

        a_uuid: MyUuid

        @field_serializer("a_uuid")
        def serialize_a_uuid(self, v):
            return str(v)

    @app.get("/get_custom_class")
    def return_some_user():
        # Test that the fix also works for custom pydantic classes
        return SomeCustomClass(a_uuid=MyUuid("b8799909-f914-42de-91bc-95c819218d01"))

    client = TestClient(app)

    with client:
        response_simple = client.get("/fast_uuid")

  
  project4["project"]
  build2 --> project4

```

### Build process state

The "build process state" holds the global state of the build process and manages all the other state.

The build process state also includes state that is tied to a particular Gradle user home directory.
When that directory changes between Gradle invocations, the state is discarded and recreated.

   1. If the certificate is not yet expired, the `SecretManager` also can return a cache response. In practice, this would
       only happen in cases where Envoy were to re-request a resource, which is fairly rare.
   1. `SecretManager` can also read certificates from files. When this is configured, no CA client is used.

/// note | "Technical Details"

A `Request` has a `request.scope` attribute, that's just a Python `dict` containing the metadata related to the request.

A `Request` also has a `request.receive`, that's a function to "receive" the body of the request.

The `scope` `dict` and `receive` function are both part of the ASGI specification.

////

In this case, the function parameter `q` will be optional, and will be `None` by default.

/// check

Also notice that **FastAPI** is smart enough to notice that the path parameter `item_id` is a path parameter and `q` is not, so, it's a query parameter.

///

## Query parameter type conversion

You can also declare `bool` types, and they will be converted:

//// tab | Python 3.10+

```Python hl_lines="7"

<img src="/img/tutorial/metadata/image01.png">

## License identifier

Since OpenAPI 3.1.0 and FastAPI 0.99.0, you can also set the `license_info` with an `identifier` instead of a `url`.

For example:

```Python hl_lines="31"
{!../../docs_src/metadata/tutorial001_1.py!}
```

## Metadata for tags

You can also add additional metadata for the different tags used to group your path operations with the parameter `openapi_tags`.

  @VisibleForTesting transient int expectedValuesPerKey = DEFAULT_VALUES_PER_KEY;

  /**
   * Creates a new, empty {@code HashMultimap} with the default initial capacities.
   *
   * <p>You may also consider the equivalent {@code
   * MultimapBuilder.hashKeys().hashSetValues().build()}, which provides more control over the
   * underlying data structure.
   */

Pass `*`, as the first parameter of the function.

Python won't do anything with that `*`, but it will know that all the following parameters should be called as keyword arguments (key-value pairs), also known as <abbr title="From: K-ey W-ord Arg-uments"><code>kwargs</code></abbr>. Even if they don't have a default value.

```Python hl_lines="7"
{!../../docs_src/path_params_numeric_validations/tutorial003.py!}
```