🖼 👆 💪 ✔️ 📁 `main.py` ⏮️:

```Python hl_lines="3"
import os

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

/// tip

🥈 ❌ <a href="https://docs.python.org/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> 🔢 💲 📨.

🚥 🚫 🚚, ⚫️ `None` 🔢, 📥 👥 🚚 `"World"` 🔢 💲 ⚙️.

///

⤴️ 👆 💪 🤙 👈 🐍 📋:

```Python hl_lines="3"
import os

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

/// tip | Dica

O segundo parâmetro em <a href="https://docs.python.org/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> é o valor padrão para o retorno.

	ldflagsStr += " -X github.com/minio/minio/cmd.GOPATH=" + os.Getenv("GOPATH")
	ldflagsStr += " -X github.com/minio/minio/cmd.GOROOT=" + os.Getenv("GOROOT")
	return ldflagsStr
}

// genReleaseTag prints release tag to the console for easy git tagging.
func releaseTag(version string) (string, time.Time) {
	relPrefix := "DEVELOPMENT"
	if prefix := os.Getenv("MINIO_RELEASE"); prefix != "" {
		relPrefix = prefix
	}

     *
     * @param key the environment variable key
     * @return the environment variable value, or null if not found
     */
    public static String getEnv(String key) {
        return System.getenv(key);
    }

    /**
     * Returns the system environment variable value for the specified key, or the default value if not found.
     *
     * @param key the environment variable key

  __path__ = [_tf_api_dir]
elif _tf_api_dir not in __path__:
  __path__.append(_tf_api_dir)

# Hook external TensorFlow modules.

# Load tensorflow-io-gcs-filesystem if enabled
if (_os.getenv("TF_USE_MODULAR_FILESYSTEM", "0") == "true" or
    _os.getenv("TF_USE_MODULAR_FILESYSTEM", "0") == "1"):
  import tensorflow_io_gcs_filesystem as _tensorflow_io_gcs_filesystem

# Lazy-load Keras v2/3.
_tf_uses_legacy_keras = (

			log.Printf("failed to ping sqlDB, got error %v", err)
			os.Exit(1)
		}

		RunMigrations()
	}
}

func OpenTestConnection(cfg *gorm.Config) (db *gorm.DB, err error) {
	dbDSN := os.Getenv("GORM_DSN")
	switch os.Getenv("GORM_DIALECT") {
	case "mysql":
		log.Println("testing mysql...")
		if dbDSN == "" {
			dbDSN = mysqlDSN
		}
		db, err = gorm.Open(mysql.Open(dbDSN), cfg)
	case "postgres":

	"context"
	"fmt"
	"log"
	"net/http"
	"os"

	cr "github.com/minio/minio-go/v7/pkg/credentials"
	cmd "github.com/minio/minio/cmd"
)

func main() {
	ctx := context.Background()

	endpoint := os.Getenv("MINIO_ENDPOINT")
	if endpoint == "" {
		log.Fatalf("Please specify a MinIO server endpoint environment variable like:\n\n\texport MINIO_ENDPOINT=http://localhost:9000")
	}

	appParams := cmd.OpenIDClientAppParams{

# lazy loading.
_current_module.compat.v2  # pylint: disable=pointless-statement

# Load tensorflow-io-gcs-filesystem if enabled
if (_os.getenv("TF_USE_MODULAR_FILESYSTEM", "0") == "true" or
    _os.getenv("TF_USE_MODULAR_FILESYSTEM", "0") == "1"):
  import tensorflow_io_gcs_filesystem as _tensorflow_io_gcs_filesystem

# Lazy-load Keras v1.
_tf_uses_legacy_keras = (

    object : ThreadFactory {
      private var nextId = 1

      override fun newThread(runnable: Runnable): Thread = Thread(runnable, "$name-${nextId++}")
    }
}

fun getEnv(name: String) = System.getenv(name)

val SYSTEM_FILE_SYSTEM = FileSystem.SYSTEM

مثلاً می‌تونی یه فایل `main.py` داشته باشی با:

```Python hl_lines="3"
import os

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

/// tip

آرگومان دوم <a href="https://docs.python.org/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> مقدار پیش‌فرضیه که برمی‌گردونه.