import warnings
from enum import Enum
from typing import Any, Callable, Dict, List, Optional, Sequence, Union

from fastapi.openapi.models import Example
from pydantic.fields import FieldInfo
from typing_extensions import Annotated, deprecated

from ._compat import PYDANTIC_V2, PYDANTIC_VERSION, Undefined

_Unset: Any = Undefined


class ParamTypes(Enum):
    query = "query"
    header = "header"
    path = "path"

Eine Python-Klasse ist also auch ein **Callable**.

Darum können Sie in **FastAPI** auch eine Python-Klasse als Abhängigkeit verwenden.

Was FastAPI tatsächlich prüft, ist, ob es sich um ein „Callable“ (Funktion, Klasse oder irgendetwas anderes) handelt und ob die Parameter definiert sind.

def is_coroutine_callable(call: Callable[..., Any]) -> bool:
    if inspect.isroutine(call):
        return inspect.iscoroutinefunction(call)
    if inspect.isclass(call):
        return False
    dunder_call = getattr(call, "__call__", None)  # noqa: B004
    return inspect.iscoroutinefunction(dunder_call)


def is_async_gen_callable(call: Callable[..., Any]) -> bool:

    set: list,
    UUID: str,
    Url: str,
    AnyUrl: str,
}


def generate_encoders_by_class_tuples(
    type_encoder_map: Dict[Any, Callable[[Any], Any]],
) -> Dict[Callable[[Any], Any], Tuple[Any, ...]]:
    encoders_by_class_tuples: Dict[Callable[[Any], Any], Tuple[Any, ...]] = defaultdict(
        tuple
    )
    for type_, encoder in type_encoder_map.items():
        encoders_by_class_tuples[encoder] += (type_,)

So, a Python class is also a **callable**.

Then, in **FastAPI**, you could use a Python class as a dependency.

What FastAPI actually checks is that it is a "callable" (function, class or anything else) and the parameters defined.

from enum import Enum
from typing import Any, Callable, Dict, Iterable, List, Optional, Set, Type, Union

from fastapi._compat import (
    PYDANTIC_V2,
    CoreSchema,
    GetJsonSchemaHandler,
    JsonSchemaValue,
    _model_rebuild,
    with_info_plain_validator_function,
)
from fastapi.logger import logger
from pydantic import AnyUrl, BaseModel, Field
from typing_extensions import Annotated, Literal, TypedDict

from collections import deque
from copy import copy
from dataclasses import dataclass, is_dataclass
from enum import Enum
from typing import (
    Any,
    Callable,
    Deque,
    Dict,
    FrozenSet,
    List,
    Mapping,
    Sequence,
    Set,
    Tuple,
    Type,
    Union,
)

from fastapi.exceptions import RequestErrorModel
from fastapi.types import IncEx, ModelNameMap, UnionType

Die Variable `oauth2_scheme` ist eine Instanz von `OAuth2PasswordBearer`, aber auch ein „Callable“.

Es könnte wie folgt aufgerufen werden:

```Python
oauth2_scheme(some, parameters)
```

Es kann also mit `Depends` verwendet werden.

### Verwendung