{!> ../../../docs_src/dependencies/tutorial011.py!}
    ```

In this case, this `__call__` is what **FastAPI** will use to check for additional parameters and sub-dependencies, and this is what will be called to pass a value to the parameter in your *path operation function* later.

## Parameterize the instance

And now, we can use `__init__` to declare the parameters of the instance that we can use to "parameterize" the dependency:

So, we need to do some extra tricks to make it work as if it was just using `threading.local`. The `__init__`, `__setattr__`, and `__getattr__` implement all the required tricks for this to be used by Peewee without knowing that it is now compatible with FastAPI.

!!! tip

pkg syscall (freebsd-arm64), const SYS___ACL_DELETE_FD ideal-int
pkg syscall (freebsd-arm64), const SYS___ACL_DELETE_FILE = 351
pkg syscall (freebsd-arm64), const SYS___ACL_DELETE_FILE ideal-int
pkg syscall (freebsd-arm64), const SYS___ACL_DELETE_LINK = 427
pkg syscall (freebsd-arm64), const SYS___ACL_DELETE_LINK ideal-int
pkg syscall (freebsd-arm64), const SYS___ACL_GET_FD = 349

```
.
├── app
│   ├── __init__.py
│   └── main.py
```

In der Datei `main.py` haben Sie Ihre **FastAPI**-Anwendung:


```Python
{!../../../docs_src/app_testing/main.py!}
```

### Testdatei

Dann könnten Sie eine Datei `test_main.py` mit Ihren Tests haben. Sie könnte sich im selben Python-Package befinden (dasselbe Verzeichnis mit einer `__init__.py`-Datei):

``` hl_lines="5"
.
├── app

                </mxCell>
                <mxCell id="3" value="&lt;font style=&quot;font-size: 24px&quot; face=&quot;Roboto&quot;&gt;Package app&lt;br&gt;app/__init__.py&lt;/font&gt;" style="text;html=1;strokeColor=none;fillColor=none;align=center;verticalAlign=middle;whiteSpace=wrap;rounded=0;strokeWidth=3;fontFamily=Roboto Mono, mono;FType=g;" parent="1" vertex="1">

```
.
├── app
│   ├── __init__.py
│   ├── main.py
│   └── test_main.py
```

The file `main.py` would have:

```Python
{!../../../docs_src/async_tests/main.py!}
```

In Python können Sie Kontextmanager erstellen, indem Sie <a href="https://docs.python.org/3/reference/datamodel.html#context-managers" class="external-link" target="_blank">eine Klasse mit zwei Methoden erzeugen: `__enter__()` und `__exit__()`</a>.

Sie können solche auch innerhalb von **FastAPI**-Abhängigkeiten mit `yield` verwenden, indem Sie `with`- oder `async with`-Anweisungen innerhalb der Abhängigkeits-Funktion verwenden:

pkg syscall (darwin-386-cgo), const SYS___MAC_GET_LINK ideal-int
pkg syscall (darwin-386-cgo), const SYS___MAC_GET_MOUNT ideal-int
pkg syscall (darwin-386-cgo), const SYS___MAC_GET_PID ideal-int
pkg syscall (darwin-386-cgo), const SYS___MAC_GET_PROC ideal-int
pkg syscall (darwin-386-cgo), const SYS___MAC_MOUNT ideal-int
pkg syscall (darwin-386-cgo), const SYS___MAC_SET_FD ideal-int

pkg syscall (netbsd-arm64-cgo), const SYS__LWP_KILL ideal-int
pkg syscall (netbsd-arm64-cgo), const SYS__LWP_PARK = 434
pkg syscall (netbsd-arm64-cgo), const SYS__LWP_PARK ideal-int
pkg syscall (netbsd-arm64-cgo), const SYS__LWP_SELF = 311
pkg syscall (netbsd-arm64-cgo), const SYS__LWP_SELF ideal-int
pkg syscall (netbsd-arm64-cgo), const SYS__LWP_SETNAME = 323

        "tfe_op_attrs_internal.h",
        "tfe_tensor_debug_info_internal.h",
        "tfe_tensorhandle_internal.h",
    ],
    visibility = [
        "//tensorflow/core/function/runtime_client:__pkg__",
        "//tensorflow/python:__subpackages__",
    ],
)

cc_library(
    name = "c_api_internal",
    hdrs = [
        "c_api_experimental.h",
        "c_api_internal.h",
    ],