## Type annotation vs `Depends` { #type-annotation-vs-depends }

Notice how we write `CommonQueryParams` twice in the above code:

//// tab | Python 3.8+

```Python
commons: Annotated[CommonQueryParams, Depends(CommonQueryParams)]
```

////

//// tab | Python 3.8+ non-Annotated

/// tip

Prefer to use the `Annotated` version if possible.

///

```Python

//// tab | لینوکس، مک‌اواس، ویندوز بش

<div class="termy">

```console
// می‌تونی یه متغیر محیطی به اسم MY_NAME بسازی با
$ export MY_NAME="Wade Wilson"

// بعد می‌تونی با برنامه‌های دیگه ازش استفاده کنی، مثل
$ echo "Hello $MY_NAME"

Hello Wade Wilson
```

</div>

////

//// tab | ویندوز پاورشل

<div class="termy">

```console

//// tab | Linux, macOS, Windows Bash

<div class="termy">

```console
// You could create an env var MY_NAME with
$ export MY_NAME="Wade Wilson"

// Then you could use it with other programs, like
$ echo "Hello $MY_NAME"

Hello Wade Wilson
```

</div>

////

//// tab | Windows PowerShell

<div class="termy">

```console

یعنی توی پایتون 3.10، می‌تونی از `Something | None` استفاده کنی:

//// tab | Python 3.10+

```Python hl_lines="1"
{!> ../../docs_src/python_types/tutorial009_py310.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="1  4"
{!> ../../docs_src/python_types/tutorial009.py!}
```

////

//// tab | Python 3.8+ جایگزین

```Python hl_lines="1  4"

This also means that in Python 3.10, you can use `Something | None`:

//// tab | Python 3.10+

```Python hl_lines="1"
{!> ../../docs_src/python_types/tutorial009_py310.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="1  4"
{!> ../../docs_src/python_types/tutorial009.py!}
```

////

//// tab | Python 3.8+ alternative

```Python hl_lines="1  4"

///

//// tab | Linux, macOS

<div class="termy">

```console
$ source .venv/bin/activate
```

</div>

////

//// tab | Windows PowerShell

<div class="termy">

```console
$ .venv\Scripts\Activate.ps1
```

</div>

////

//// tab | Windows Bash

Both *path operations* require an `X-Token` header.

//// tab | Python 3.10+

```Python
{!> ../../docs_src/app_testing/app_b_an_py310/main.py!}
```

////

//// tab | Python 3.9+

```Python
{!> ../../docs_src/app_testing/app_b_an_py39/main.py!}
```

////

//// tab | Python 3.8+

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

We had this type annotation:

//// tab | Python 3.10+

```Python
q: str | None = None
```

////

//// tab | Python 3.8+

```Python
q: Union[str, None] = None
```

////

What we will do is wrap that with `Annotated`, so it becomes:

//// tab | Python 3.10+

```Python
q: Annotated[str | None] = None
```

////

//// tab | Python 3.8+

```Python

//// tab | Pydantic v2

{* ../../docs_src/schema_extra_example/tutorial001_py310.py hl[13:24] *}

////

//// tab | Pydantic v1

{* ../../docs_src/schema_extra_example/tutorial001_pv1_py310.py hl[13:23] *}

////

Ця додаткова інформація буде додана як є до **JSON-схеми**, і вона буде використовуватися в документації до API.

//// tab | Pydantic v2

//// tab | Pydantic v2

{* ../../docs_src/path_operation_advanced_configuration/tutorial007.py hl[17:22, 24] *}

////

//// tab | Pydantic v1

{* ../../docs_src/path_operation_advanced_configuration/tutorial007_pv1.py hl[17:22, 24] *}

////

/// info