if not scopes:
            scopes = {}
        flows = OAuthFlowsModel(
            password=cast(
                Any,
                {
                    "tokenUrl": tokenUrl,
                    "refreshUrl": refreshUrl,
                    "scopes": scopes,
                },
            )
        )
        super().__init__(
            flows=flows,
            scheme_name=scheme_name,

from fastapi.security import OAuth2, OAuth2PasswordRequestFormStrict
from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()

reusable_oauth2 = OAuth2(
    flows={
        "password": {
            "tokenUrl": "token",
            "scopes": {"read:users": "Read the users", "write:users": "Create users"},
        }
    },
    auto_error=False,
)

from fastapi.security import OAuth2, OAuth2PasswordRequestFormStrict
from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()

reusable_oauth2 = OAuth2(
    flows={
        "password": {
            "tokenUrl": "token",
            "scopes": {"read:users": "Read the users", "write:users": "Create users"},
        }
    }
)


class User(BaseModel):
    username: str

from fastapi.security import OAuth2, OAuth2PasswordRequestFormStrict
from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()

reusable_oauth2 = OAuth2(
    flows={
        "password": {
            "tokenUrl": "token",
            "scopes": {"read:users": "Read the users", "write:users": "Create users"},
        }
    },
    description="OAuth2 security scheme",

            },
            "components": {
                "securitySchemes": {
                    "OAuth2AuthorizationCodeBearer": {
                        "type": "oauth2",
                        "flows": {
                            "authorizationCode": {
                                "scopes": {
                                    "read": "Read access",
                                    "write": "Write access",

                }
            },
            "components": {
                "securitySchemes": {
                    "OAuth2AuthorizationCodeBearer": {
                        "type": "oauth2",
                        "flows": {
                            "authorizationCode": {
                                "scopes": {
                                    "read": "Read access",
                                    "write": "Write access",

                }
            }
        },
        "components": {
            "securitySchemes": {
                "OAuth2PasswordBearer": {
                    "type": "oauth2",
                    "flows": {"password": {"scopes": {}, "tokenUrl": "token"}},
                }
            },
        },

                    },
                },
            },
            "securitySchemes": {
                "OAuth2PasswordBearer": {
                    "type": "oauth2",
                    "flows": {"password": {"scopes": {}, "tokenUrl": "token"}},
                }
            },
        },

                }
            }
        },
        "components": {
            "securitySchemes": {
                "OAuth2PasswordBearer": {
                    "type": "oauth2",
                    "flows": {"password": {"scopes": {}, "tokenUrl": "token"}},
                }
            }
        },

Самый распространённый — «implicit flow».

Самый безопасный — «code flow», но он сложнее в реализации, так как требует больше шагов. Из‑за сложности многие провайдеры в итоге рекомендуют «implicit flow».

/// note | Примечание

Часто каждый провайдер аутентификации называет свои «flows» по‑разному — как часть бренда.