import re

import warnings

from dataclasses import is_dataclass

from typing import TYPE_CHECKING, Any, Dict, MutableMapping, Optional, Set, Type, Union, cast

from weakref import WeakKeyDictionary

import fastapi

from fastapi._compat import PYDANTIC_V2, BaseConfig, ModelField, PydanticSchemaGenerationError, Undefined, UndefinedType, Validator, lenient_issubclass

from fastapi.datastructures import DefaultPlaceholder, DefaultType

from pydantic import BaseModel, create_model

from pydantic.fields import FieldInfo

from typing_extensions import Literal

if TYPE_CHECKING:

from .routing import APIRoute

_CLONED_TYPES_CACHE: MutableMapping[Type[BaseModel], Type[BaseModel]] = WeakKeyDictionary()

def create_response_field(name: str, type_: Type[Any], class_validators: Optional[Dict[str, Validator]]=None, default: Optional[Any]=Undefined, required: Union[bool, UndefinedType]=Undefined, model_config: Type[BaseConfig]=BaseConfig, field_info: Optional[FieldInfo]=None, alias: Optional[str]=None, mode: Literal['validation', 'serialization']='validation') -> ModelField:

pass

def get_value_or_default(first_item: Union[DefaultPlaceholder, DefaultType], *extra_items: Union[DefaultPlaceholder, DefaultType]) -> Union[DefaultPlaceholder, DefaultType]: