Also fügen wir sie in ihr eigenes `dependencies`-Modul (`app/dependencies.py`) ein.

Wir werden nun eine einfache Abhängigkeit verwenden, um einen benutzerdefinierten `X-Token`-Header zu lesen:

//// tab | Python 3.9+

```Python hl_lines="3  6-8" title="app/dependencies.py"
{!> ../../docs_src/bigger_applications/app_an_py39/dependencies.py!}
```

////

//// tab | Python 3.8+

```

Read the new docs: [Query Parameter Models](https://fastapi.tiangolo.com/tutorial/query-param-models/).

#### `Header` Parameter Models

Use Pydantic models for `Header` parameters:

```python
from typing import Annotated

from fastapi import FastAPI, Header
from pydantic import BaseModel

app = FastAPI()


class CommonHeaders(BaseModel):
    host: str
    save_data: bool

  /**
   * Returns true if this cookie's domain should be interpreted as a single host name, or false if
   * it should be interpreted as a pattern. This flag will be false if its `Set-Cookie` header
   * included a `domain` attribute.
   *
   * For example, suppose the cookie's domain is `example.com`. If this flag is true it matches

    * JSON.
    * <abbr title="Yol: Path">Yol</abbr> parametrləri.
    * <abbr title="Sorğu: Query">Sorğu</abbr> parametrləri.
    * <abbr title="Çərəz: Cookie">Çərəzlər</abbr>.
    * <abbr title="Başlıq: Header">Başlıqlaq</abbr>.
    * <abbr title="Forma: Form">Formalar</abbr>.
    * Fayllar.

   *     CLEAN 1ab96a171faeeee38496d8b330771a7a 1600 234
   *     READ 335c4c6028171cfddfbaae1a9c313c52
   *     READ 3400330d1dfc7f3f7f4b8d4d803dfcf6
   *
   * The first five lines of the journal form its header. They are the constant string
   * "libcore.io.DiskLruCache", the disk cache's version, the application's version, the value
   * count, and a blank line.
   *

    assertEquals("a", elementSet.first());
    assertEquals("c", elementSet.last());
    assertEquals(Ordering.natural(), elementSet.comparator());

    assertThat(elementSet.headSet("b")).containsExactly("a");
    assertThat(elementSet.tailSet("b")).containsExactly("b", "c").inOrder();
    assertThat(elementSet.subSet("a", "c")).containsExactly("a", "b").inOrder();
  }

It has a `GET` operation that could return an error.

It has a `POST` operation that could return several errors.

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

&.show { opacity: $modal-backdrop-opacity; }\n}\n\n// Modal header\n// Top section of the modal w/ title and dismiss\n.modal-header {\n  display: flex;\n  align-items: flex-start; // so the close btn always stays on the upper right corner\n  justify-content: space-between; // Put modal header elements (title and dismiss) on opposite ends\n  padding: $modal-header-padding;\n  border-bottom: $modal-header-border-width solid $modal-header-border-color;\n  @include border-top-radius($modal-content-i...

		header, zerr := zip.FileInfoHeader(dummyFileInfo{
			name:    filename,
			size:    int64(sz),
			mode:    0o600,
			modTime: time.Now(),
			isDir:   false,
			sys:     nil,
		})
		if zerr != nil {
			adminLogIf(ctx, zerr)
			return nil
		}
		header.Method = zip.Deflate
		zwriter, zerr := zipWriter.CreateHeader(header)
		if zerr != nil {

lc(.25rem - 1px);border-bottom-left-radius:calc(.25rem - 1px)}.card>.card-header+.list-group,.card>.list-group+.card-footer{border-top:0}.card-body{-ms-flex:1 1 auto;flex:1 1 auto;min-height:1px;padding:1.25rem}.card-title{margin-bottom:.75rem}.card-subtitle{margin-top:-.375rem;margin-bottom:0}.card-text:last-child{margin-bottom:0}.card-link:hover{text-decoration:none}.card-link+.card-link{margin-left:1.25rem}.card-header{padding:.75rem 1.25rem;margin-bottom:0;background-color:rgba(0,0,0,.03);border-bottom:1px...