input.value = ''
                event.preventDefault()
            }
        </script>
    </body>
</html>
"""


@app.get("/")
async def get():
    return HTMLResponse(html)


@app.websocket("/ws")
async def websocket_endpoint(websocket: WebSocket):
    await websocket.accept()
    while True:
        data = await websocket.receive_text()

@app.get("/items/{item_id}", response_model=Item)
async def read_main(item_id: str, x_token: str = Header()):
    if x_token != fake_secret_token:
        raise HTTPException(status_code=400, detail="Invalid X-Token header")
    if item_id not in fake_db:
        raise HTTPException(status_code=404, detail="Item not found")
    return fake_db[item_id]


@app.post("/items/")
async def create_item(item: Item, x_token: str = Header()) -> Item:

                }
            } else {
                log.warn("Async notify failed: {}", message.getErrorMessage());
            }

            return null;

        } catch (Exception e) {
            throw new IOException("Witness async notify RPC failed", e);
        }
    }

    /**
     * Generates a registration ID from context handle and share name.

# Alias


@app.get("/required-list-alias")
async def read_required_list_alias(p: Annotated[list[str], Query(alias="p_alias")]):
    return {"p": p}


class QueryModelRequiredListAlias(BaseModel):
    p: list[str] = Field(alias="p_alias")


@app.get("/model-required-list-alias")
async def read_model_required_list_alias(
    p: Annotated[QueryModelRequiredListAlias, Query()],
):

<details markdown="1">
<summary>Або використайте <code>async def</code>...</summary>

Якщо ваш код використовує `async` / `await`, скористайтеся `async def`:

```Python hl_lines="7  12"
from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
async def read_item(item_id: int, q: str | None = None):

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_main():

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def root():

from fastapi import FastAPI

app = FastAPI()


@app.get("/items/", include_in_schema=False)
async def read_items():

from fastapi import FastAPI, Form

app = FastAPI()


@app.post("/login/")
async def login(username: str = Form(), password: str = Form()):

from fastapi import FastAPI, Header

app = FastAPI()


@app.get("/items/")
async def read_items(user_agent: str | None = Header(default=None)):