Pydantic’te [`BeforeValidator`](https://docs.pydantic.dev/latest/concepts/validators/#field-before-validator) ve başka validator’lar da vardır. 🤓

///

///

Zum Beispiel überprüft dieser benutzerdefinierte Validator, ob die Artikel-ID mit `isbn-` für eine <abbr title="International Standard Book Number - Internationale Standardbuchnummer">ISBN</abbr>-Buchnummer oder mit `imdb-` für eine <abbr title="Internet Movie Database - Internet-Filmdatenbank: eine Website mit Informationen über Filme">IMDB</abbr>-Film-URL-ID beginnt:

///

Por exemplo, este validador personalizado verifica se o ID do item começa com `isbn-` para um número de livro <abbr title="International Standard Book Number - Número Padrão Internacional de Livro">ISBN</abbr> ou com `imdb-` para um ID de URL de filme <abbr title="Internet Movie Database - Base de Dados de Filmes da Internet: um site com informações sobre filmes">IMDB</abbr>:

/// tip | 提示

Pydantic 也有 [`BeforeValidator`](https://docs.pydantic.dev/latest/concepts/validators/#field-before-validator) 等等。🤓

///

例如，以下自訂驗證器會檢查項目 ID 是否以 `isbn-` 開頭（<abbr title="International Standard Book Number - 國際標準書號">ISBN</abbr> 書籍編號），或以 `imdb-` 開頭（<abbr title="Internet Movie Database - 互聯網電影資料庫: 含有電影資訊的網站">IMDB</abbr> 電影 URL 的 ID）：

{* ../../docs_src/query_params_str_validations/tutorial015_an_py310.py hl[5,16:19,24] *}

			name:   "list keys as user set policy that allows listing but denies specific keys",
			method: http.MethodGet,
			path:   kmsKeyListPath,
			query:  map[string]string{"pattern": "*"},
			asRoot: false,

			// It looks like this should allow listing any key that isn't "default-test-key", however
			// the policy engine matches all Deny statements first, without regard to Resources (for KMS).

///

	if newGlobalAuthZPluginFn() != nil {
		return claims, nil
	}

	// Check if a session policy is set. If so, decode it here.
	sp, spok := claims.Lookup(policy.SessionPolicyName)
	if spok {
		// Looks like subpolicy is set and is a string, if set then its
		// base64 encoded, decode it. Decoding fails reject such
		// requests.
		spBytes, err := base64.StdEncoding.DecodeString(sp)
		if err != nil {

      if (initialized) {
        cleanupQueue.schedule(cleanupTask) // Trim the existing store if necessary.
      }
    }

  /*
   * This cache uses a journal file named "journal". A typical journal file looks like this:
   *
   *     libcore.io.DiskLruCache
   *     1
   *     100
   *     2
   *
   *     CLEAN 3400330d1dfc7f3f7f4b8d4d803dfcf6 832 21054
   *     DIRTY 335c4c6028171cfddfbaae1a9c313c52

      annotatedTypeExists()
          ? NullnessAnnotationReader.FROM_DECLARATION_AND_TYPE_USE_ANNOTATIONS
          : NullnessAnnotationReader.FROM_DECLARATION_ANNOTATIONS_ONLY;

  /**
   * Looks for declaration nullness annotations and, if supported, type-use nullness annotations.
   *
   * <p>Under Android VMs, the methods for retrieving type-use annotations don't exist. This means

///

Por ejemplo, este validador personalizado comprueba que el ID del ítem empiece con `isbn-` para un número de libro <abbr title="International Standard Book Number - Número Estándar Internacional de Libros">ISBN</abbr> o con `imdb-` para un ID de URL de película de <abbr title="Internet Movie Database - Base de datos de películas en Internet: un sitio web con información sobre películas">IMDB</abbr>: