## Usando `BackgroundTasks` { #using-backgroundtasks }

Primero, importa `BackgroundTasks` y define un parámetro en tu *path operation function* con una declaración de tipo de `BackgroundTasks`:

{* ../../docs_src/background_tasks/tutorial001_py39.py hl[1,13] *}

	}

	stmt := gorm.Statement{DB: DB}
	if err := stmt.Parse(&EngadgetPost{}); err != nil {
		t.Fatalf("failed to parse embedded struct")
	} else if len(stmt.Schema.PrimaryFields) != 1 {
		t.Errorf("should have only one primary field with embedded struct, but got %v", len(stmt.Schema.PrimaryFields))
	}

	for _, name := range []string{"user_id", "user_name", "user_email"} {
		if !DB.Migrator().HasColumn(&HNPost{}, name) {

        return doGetConditionQuery();
    }

    // ===================================================================================
    //                                                                         Primary Key
    //                                                                         ===========
    public CrawlingInfoParamCB acceptPK(String id) {
        assertObjectNotNull("id", id);
        BsCrawlingInfoParamCB cb = this;

                        <div
                                class="card card-outline <c:if test="${crudMode == 1 || crudMode == 2}">card-success</c:if><c:if test="${crudMode == 3}">card-danger</c:if><c:if test="${crudMode == 4}">card-primary</c:if>">
                                <%-- Card Header --%>
                            <div class="card-header">
                                <jsp:include page="/WEB-INF/view/common/admin/crud/header.jsp"></jsp:include>

```

ou

```
http://127.0.0.1:8000/items/foo?short=on
```

ou

```
http://127.0.0.1:8000/items/foo?short=yes
```

ou qualquer outra variação (tudo em maiúscula, primeira letra em maiúscula, etc), a sua função vai ver o parâmetro `short` com um valor `bool` de `True`. Caso contrário `False`.

## Múltiplos parâmetros de rota e consulta { #multiple-path-and-query-parameters }

{* ../../docs_src/security/tutorial001_an_py39.py hl[12] *}

Pero eso aún no es tan útil. Vamos a hacer que nos dé el usuario actual.

## Crear un modelo de usuario { #create-a-user-model }

Primero, vamos a crear un modelo de usuario con Pydantic.

De la misma manera que usamos Pydantic para declarar cuerpos, podemos usarlo en cualquier otra parte:

{* ../../docs_src/security/tutorial002_an_py310.py hl[5,12:6] *}

        return doGetConditionQuery();
    }

    // ===================================================================================
    //                                                                         Primary Key
    //                                                                         ===========
    public BoostDocumentRuleCB acceptPK(String id) {
        assertObjectNotNull("id", id);
        BsBoostDocumentRuleCB cb = this;

        return doGetConditionQuery();
    }

    // ===================================================================================
    //                                                                         Primary Key
    //                                                                         ===========
    public FileAuthenticationCB acceptPK(String id) {
        assertObjectNotNull("id", id);
        BsFileAuthenticationCB cb = this;

        return doGetConditionQuery();
    }

    // ===================================================================================
    //                                                                         Primary Key
    //                                                                         ===========
    public KeyMatchCB acceptPK(String id) {
        assertObjectNotNull("id", id);
        BsKeyMatchCB cb = this;

        return doGetConditionQuery();
    }

    // ===================================================================================
    //                                                                         Primary Key
    //                                                                         ===========
    public LabelTypeCB acceptPK(String id) {
        assertObjectNotNull("id", id);
        BsLabelTypeCB cb = this;