Por ejemplo, podrías tener un archivo `main.py` con:

```Python hl_lines="3"
import os

name = os.getenv("MY_NAME", "World")
print(f"Hello {name} from Python")
```

/// tip | Consejo

El segundo argumento de <a href="https://docs.python.org/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> es el valor por defecto a retornar.

///

Lo único nuevo es `callbacks=invoices_callback_router.routes` como un argumento para el *decorador de path operation*. Veremos qué es eso a continuación.

## Documentar el callback { #documenting-the-callback }

El código real del callback dependerá mucho de tu propia aplicación API.

        optimizedHelper.setProperty(bean2, "count", Integer.class, config2);
    }

    /**
     * Main method to run the JMH benchmark.
     *
     * @param args command line arguments
     * @throws RunnerException if the benchmark fails to run
     */
    public static void main(String[] args) throws RunnerException {
        Options opt = new OptionsBuilder()

Nimm die Schlüssel-Wert-Paare des `second_user_data` <abbr title="Dictionary – Zuordnungstabelle: In anderen Sprachen auch Hash, Map, Objekt, Assoziatives Array genannt">Dicts</abbr> und übergebe sie direkt als Schlüsselwort-Argumente. Äquivalent zu: `User(id=4, name="Mary", joined="2018-11-30")`

///

### Editor Unterstützung { #editor-support }

    "joined": "2018-11-30",
}

my_second_user: User = User(**second_user_data)
```

/// info

`**second_user_data` means:

Pass the keys and values of the `second_user_data` dict directly as key-value arguments, equivalent to: `User(id=4, name="Mary", joined="2018-11-30")`

///

### Editor support { #editor-support }

	EnvMySQLQueueDir           = "MINIO_NOTIFY_MYSQL_QUEUE_DIR"
	EnvMySQLMaxOpenConnections = "MINIO_NOTIFY_MYSQL_MAX_OPEN_CONNECTIONS"
)

// MySQLArgs - MySQL target arguments.
type MySQLArgs struct {
	Enable             bool     `json:"enable"`
	Format             string   `json:"format"`
	DSN                string   `json:"dsnString"`
	Table              string   `json:"table"`

{* ../../docs_src/path_params/tutorial001_py39.py hl[6:7] *}

O valor do parâmetro de path `item_id` será passado para a sua função como o argumento `item_id`.

Então, se você executar este exemplo e acessar <a href="http://127.0.0.1:8000/items/foo" class="external-link" target="_blank">http://127.0.0.1:8000/items/foo</a>, você verá uma resposta:

```JSON
{"item_id":"foo"}

import (
	"context"
	"net/http"
	"strconv"
	"strings"

	"github.com/minio/minio/internal/logger"
	"github.com/minio/mux"

	"github.com/minio/pkg/v3/policy"
)

// Validate all the ListObjects query arguments, returns an APIErrorCode
// if one of the args do not meet the required conditions.
// Special conditions required by MinIO server are as below
//   - delimiter if set should be equal to '/', otherwise the request is rejected.

// the suffix for the configured queue dir where the logs will be persisted.
const kafkaLoggerExtension = ".kafka.log"

const (
	statusClosed = iota
	statusOffline
	statusOnline
)

// Config - kafka target arguments.
type Config struct {
	Enabled bool        `json:"enable"`
	Brokers []xnet.Host `json:"brokers"`
	Topic   string      `json:"topic"`
	Version string      `json:"version"`
	TLS     struct {

	EnvNATSStreamingMaxPubAcksInFlight = "MINIO_NOTIFY_NATS_STREAMING_MAX_PUB_ACKS_IN_FLIGHT"

	// Jetstream constants
	EnvNATSJetStream = "MINIO_NOTIFY_NATS_JETSTREAM"
)

// NATSArgs - NATS target arguments.
type NATSArgs struct {
	Enable            bool      `json:"enable"`
	Address           xnet.Host `json:"address"`
	Subject           string    `json:"subject"`
	Username          string    `json:"username"`