## Classes as dependencies { #classes-as-dependencies_1 }

You might notice that to create an instance of a Python class, you use that same syntax.

For example:

```Python
class Cat:
    def __init__(self, name: str):
        self.name = name


fluffy = Cat(name="Mr Fluffy")
```

In this case, `fluffy` is an instance of the class `Cat`.

And to create `fluffy`, you are "calling" `Cat`.

	Algorithm string   // The sealing algorithm used to encrypt the object key.
}

// Seal encrypts the ObjectKey using the 256 bit external key and IV. The sealed
// key is also cryptographically bound to the object's path (bucket/object) and the
// domain (SSE-C or SSE-S3).
func (key ObjectKey) Seal(extKey []byte, iv [32]byte, domain, bucket, object string) SealedKey {
	if len(extKey) != 32 {

    tags:
      - v2.**
  schedule:
    - cron: '0 2 * * *'

permissions:
  contents: read

jobs:
  build:
    if: github.repository == 'tensorflow/tensorflow' # Don't do this in forks
    runs-on: [self-hosted, linux, ARM64]
    strategy:
      matrix:
        pyver: ['3.10']
    steps:
      - name: Stop old running containers (if any)
        shell: bash
        run: |

Ele será gerado apenas uma vez, e o mesmo esquema armazenado em cache será utilizado nas próximas requisições.

{* ../../docs_src/extending_openapi/tutorial001_py39.py hl[13:14,25:26] *}

### Sobrescrever o método { #override-the-method }

Agora, você pode substituir o método `.openapi()` pela sua nova função.

{* ../../docs_src/extending_openapi/tutorial001_py39.py hl[29] *}

Assim, `0.5` seria um valor válido. Mas `0.0` ou `0` não seriam.

E o mesmo para <abbr title="less than – menor que"><code>lt</code></abbr>.

El beneficio de lanzar una excepción en lugar de `return`ar un valor será más evidente en la sección sobre Dependencias y Seguridad.

En este ejemplo, cuando el cliente solicita un ítem por un ID que no existe, lanza una excepción con un código de estado de `404`:

De manera similar, no puedes redefinir una path operation:

{* ../../docs_src/path_params/tutorial003b_py39.py hl[6,11] *}

La primera siempre será utilizada ya que el path coincide primero.

## Valores predefinidos { #predefined-values }

      description: Please describe the issue you encountered.
    validations:
      required: true

  - type: textarea
    attributes:
      label: Example
      description: >
        Please provide a [Short, Self Contained, Correct (Compilable), Example](http://sscce.org/)
        demonstrating the bug.
      render: java
    validations:
      required: true

  - type: textarea
    attributes:

    branches:
      - r2.**
  schedule:
    - cron: '0 8 * * *'

permissions:
  contents: read

jobs:
  build:
    if: github.repository == 'tensorflow/tensorflow' # Don't do this in forks
    runs-on: [self-hosted, linux, ARM64]
    strategy:
      fail-fast: false
      matrix:
        pyver: ['3.9', '3.10', '3.11', '3.12']
    steps:
      - name: Stop old running containers (if any)
        shell: bash

        if (log.isDebugEnabled()) {
            log.debug("Seal key is " + Hexdump.toHexString(this.sealClientKey));
        }

        this.sealServerKey = deriveKey(mk, S2C_SEAL_CONSTANT);
        this.sealServerHandle = Crypto.getArcfour(this.sealServerKey);

        if (log.isDebugEnabled()) {
            log.debug("Server seal key is " + Hexdump.toHexString(this.sealServerKey));
        }
    }