def main() -> None:
    if not cli_main:  # type: ignore[truthy-function]
        message = 'To use the fastapi command, please install "fastapi[standard]":\n\n\tpip install "fastapi[standard]"\n'
        print(message)
        raise RuntimeError(message)  # noqa: B904

from fastapi import FastAPI, HTTPException

app = FastAPI()

items = {"foo": "The Foo Wrestlers"}


@app.get("/items-header/{item_id}")
async def read_item_header(item_id: str):
    if item_id not in items:
        raise HTTPException(
            status_code=404,
            detail="Item not found",
            headers={"X-Error": "There goes my error"},
        )

        content={"message": f"Oops! {exc.name} did something. There goes a rainbow..."},
    )


@app.get("/unicorns/{name}")
async def read_unicorn(name: str):
    if name == "yolo":
        raise UnicornException(name=name)

    correct_password_bytes = b"swordfish"
    is_correct_password = secrets.compare_digest(
        current_password_bytes, correct_password_bytes
    )
    if not (is_correct_username and is_correct_password):
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Incorrect username or password",
            headers={"WWW-Authenticate": "Basic"},
        )
    return credentials.username

    print(f"OMG! The client sent invalid data!: {exc}")
    return await request_validation_exception_handler(request, exc)


@app.get("/items/{item_id}")
async def read_item(item_id: int):
    if item_id == 3:
        raise HTTPException(status_code=418, detail="Nope! I don't like 3.")

    "isbn-9781439512982": "Isaac Asimov: The Complete Stories, Vol. 2",
}


def check_valid_id(id: str):
    if not id.startswith(("isbn-", "imdb-")):
        raise ValueError('Invalid ID format, it must start with "isbn-" or "imdb-"')
    return id


@app.get("/items/")
async def read_items(
    id: Annotated[str | None, AfterValidator(check_valid_id)] = None,
):
    if id:

    with Session(engine) as session:
        yield session


def get_user(user_id: int, session: Annotated[Session, Depends(get_session)]):
    user = session.get(User, user_id)
    if not user:
        raise HTTPException(status_code=403, detail="Not authorized")
    session.close()


def generate_stream(query: str):
    for ch in query:
        yield ch
        time.sleep(0.1)

  Returns:
    boolean value of the variable.

  Raises:
    UserInputError: if an environment variable is set, but it cannot be
      interpreted as a boolean indicator, assume that the user has made a
      scripting error, and will continue to provide invalid input.
      Raise the error to avoid infinitely looping.
  """
  if not question:

        logging.error(response.text)
        raise RuntimeError(response.text)
    data = response.json()
    if "errors" in data:
        logging.error(f"Errors in response, after: {after}")
        logging.error(data["errors"])
        logging.error(response.text)
        raise RuntimeError(response.text)
    return data


def get_graphql_pr_edges(

{* ../../docs_src/authentication_error_status_code/tutorial001_an_py39.py hl[9:13] *}

/// tip

Notice that the function returns the exception instance, it doesn't raise it. The raising is done in the rest of the internal code.