## Parametrizar la instance { #parameterize-the-instance }

Y ahora, podemos usar `__init__` para declarar los parámetros de la instance que podemos usar para "parametrizar" la dependencia:

{* ../../docs_src/dependencies/tutorial011_an_py39.py hl[9] *}

      }
    },

    /**
     * Disables cycle detection. This option causes the factory to return unmodified lock
     * implementations provided by the JDK, and is provided to allow applications to easily
     * parameterize when cycle detection is enabled.
     *
     * <p>Note that locks created by a factory with this policy will not participate the
     * cycle detection performed by locks created by other factories.
     */

      }
    },

    /**
     * Disables cycle detection. This option causes the factory to return unmodified lock
     * implementations provided by the JDK, and is provided to allow applications to easily
     * parameterize when cycle detection is enabled.
     *
     * <p>Note that locks created by a factory with this policy will not participate the
     * cycle detection performed by locks created by other factories.
     */

     * </p>
     * <p>
     * If <code>type</code> is a parameterized type but has no direct type arguments, an empty array is returned.
     * This includes cases where the parameterized type contains nested types without type arguments.
     * </p>
     * <p>
     * If <code>type</code> is not a parameterized type, <code>null</code> is returned.
     * </p>
     *
     * @param type

            "p": {"title": "P", "type": "string"},
        },
        "required": ["p"],
        "title": body_model_name,
        "type": "object",
    }


@pytest.mark.parametrize("json", [None, {}])
@pytest.mark.parametrize(
    "path",
    ["/required-str", "/model-required-str"],
)
def test_required_str_missing(path: str, json: Union[dict[str, Any], None]):
    client = TestClient(app)

            "in": "header",
        }
    ]


@pytest.mark.parametrize(
    "path",
    ["/optional-str", "/model-optional-str"],
)
def test_optional_str_missing(path: str):
    client = TestClient(app)
    response = client.get(path)
    assert response.status_code == 200
    assert response.json() == {"p": None}


@pytest.mark.parametrize(
    "path",
    ["/optional-str", "/model-optional-str"],
)

class HeaderModelRequiredStr(BaseModel):
    p: str


@app.get("/model-required-str")
async def read_model_required_str(p: Annotated[HeaderModelRequiredStr, Header()]):
    return {"p": p.p}


@pytest.mark.parametrize(
    "path",
    ["/required-str", "/model-required-str"],
)
def test_required_str_schema(path: str):
    assert app.openapi()["paths"][path]["get"]["parameters"] == [
        {
            "required": True,

    }


@pytest.mark.parametrize(
    "path",
    [
        "/optional-list-bytes",
        "/optional-list-uploadfile",
    ],
)
def test_optional_list_missing(path: str):
    client = TestClient(app)
    response = client.post(path)
    assert response.status_code == 200, response.text
    assert response.json() == {"file_size": None}


@pytest.mark.parametrize(
    "path",
    [

        ],
    }


@pytest.mark.parametrize(
    "path",
    ["/optional-list-str", "/model-optional-list-str"],
)
def test_optional_list_str_missing_empty_dict(path: str):
    client = TestClient(app)
    response = client.post(path, json={})
    assert response.status_code == 200, response.text
    assert response.json() == {"p": None}


@pytest.mark.parametrize(
    "path",

    }


@pytest.mark.parametrize(
    "path",
    [
        "/optional-bytes",
        "/optional-uploadfile",
    ],
)
def test_optional_missing(path: str):
    client = TestClient(app)
    response = client.post(path)
    assert response.status_code == 200, response.text
    assert response.json() == {"file_size": None}


@pytest.mark.parametrize(
    "path",
    [