```
1 validation error
path -> item_id
  value is not a valid integer (type=type_error.integer)
```

#### `RequestValidationError` vs. `ValidationError`

!!! warning "Achtung"
    Das folgende sind technische Details, die Sie überspringen können, wenn sie für Sie nicht wichtig sind.

Os status codes na faixa dos 400 significam que houve um erro por parte do cliente.

Você se lembra de todos aqueles erros (e piadas) a respeito do "**404 Not Found**"?

## Use o `HTTPException`

Para retornar ao cliente *responses* HTTP com erros, use o `HTTPException`.

### Import `HTTPException`

```Python hl_lines="1"
{!../../../docs_src/handling_errors/tutorial001.py!}
```

pkg net/netip, func ParseAddr(string) (Addr, error)
pkg net/netip, func ParseAddrPort(string) (AddrPort, error)
pkg net/netip, func ParsePrefix(string) (Prefix, error)
pkg net/netip, func PrefixFrom(Addr, int) Prefix
pkg net/netip, method (*Addr) UnmarshalBinary([]uint8) error
pkg net/netip, method (*Addr) UnmarshalText([]uint8) error
pkg net/netip, method (*AddrPort) UnmarshalBinary([]uint8) error

      }
    }

    override fun iterator() = error("unsupported")

    override fun offer(e: T) = error("unsupported")

    override fun peek(): T = error("unsupported")

    override fun offer(
      element: T,
      timeout: Long,
      unit: TimeUnit,
    ) = error("unsupported")

    override fun take() = error("unsupported")

    message = "moved to val",
    replaceWith = ReplaceWith(expression = "noCache"),
    level = DeprecationLevel.ERROR,
  )
  fun noCache(): Boolean = noCache

  @JvmName("-deprecated_noStore")
  @Deprecated(
    message = "moved to val",
    replaceWith = ReplaceWith(expression = "noStore"),
    level = DeprecationLevel.ERROR,
  )
  fun noStore(): Boolean = noStore

  @JvmName("-deprecated_maxAgeSeconds")
  @Deprecated(

```
1 validation error
path -> item_id
  value is not a valid integer (type=type_error.integer)
```

#### `RequestValidationError` или `ValidationError`

!!! warning "Внимание"
    Это технические детали, которые можно пропустить, если они не важны для вас сейчас.

    streamId: Int,
  ) {
    if (streamId == 0) throw IOException("PROTOCOL_ERROR: TYPE_DATA streamId == 0")

    // TODO: checkState open or half-closed (local) or raise STREAM_CLOSED
    val inFinished = flags and FLAG_END_STREAM != 0
    val gzipped = flags and FLAG_COMPRESSED != 0
    if (gzipped) {
      throw IOException("PROTOCOL_ERROR: FLAG_COMPRESSED without SETTINGS_COMPRESS_DATA")
    }

    message = "moved to val",
    replaceWith = ReplaceWith(expression = "url"),
    level = DeprecationLevel.ERROR,
  )
  fun url(): HttpUrl = url

  @JvmName("-deprecated_method")
  @Deprecated(
    message = "moved to val",
    replaceWith = ReplaceWith(expression = "method"),
    level = DeprecationLevel.ERROR,
  )
  fun method(): String = method

  @JvmName("-deprecated_headers")
  @Deprecated(

Now, get the user data from the (fake) database, using the `username` from the form field.

If there is no such user, we return an error saying "Incorrect username or password".

For the error, we use the exception `HTTPException`:

=== "Python 3.10+"

    ```Python hl_lines="3  79-81"
    {!> ../../../docs_src/security/tutorial003_an_py310.py!}
    ```

以下のようなテキスト版を取得します:

```
1 validation error
path -> item_id
  value is not a valid integer (type=type_error.integer)
```

#### `RequestValidationError`と`ValidationError`

!!! warning "注意"
    これらは今のあなたにとって重要でない場合は省略しても良い技術的な詳細です。

`RequestValidationError`はPydanticの<a href="https://docs.pydantic.dev/latest/concepts/models/#error-handling" class="external-link" target="_blank">`ValidationError`</a>のサブクラスです。