Zum Beispiel könnten Sie eine Datei `main.py` haben mit:

```Python hl_lines="3"
import os

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

/// tip | Tipp

Das zweite Argument von <a href="https://docs.python.org/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> ist der Defaultwert, der zurückgegeben wird.

	if isTiDB() {
		t.Skipf("This test case skipped, because of TiDB '%s'", reason)
	}
}

func isTiDB() bool {
	return os.Getenv("GORM_DIALECT") == "tidb"
}

func isMysql() bool {
	return os.Getenv("GORM_DIALECT") == "mysql"
}

func isSqlite() bool {
	return os.Getenv("GORM_DIALECT") == "sqlite"
}

func db(unscoped bool) *gorm.DB {
	if unscoped {
		return DB.Unscoped()
	} else {

Por exemplo, você poderia ter um arquivo `main.py` com:

```Python hl_lines="3"
import os

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

/// tip | Dica

O segundo argumento para <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 a ser retornado.

    public static final String NAME = "CircleCI";

    private static final String CIRCLECI = "CIRCLECI";

    @Override
    public Optional<CIInfo> detectCI() {
        String ciEnv = System.getenv(CIRCLECI);
        if ("true".equals(ciEnv)) {
            return Optional.of(new CIInfo() {
                @Override
                public String name() {
                    return NAME;
                }

    public static final String NAME = "Jenkins";

    private static final String WORKSPACE = "WORKSPACE";

    @Override
    public Optional<CIInfo> detectCI() {
        String workspace = System.getenv(WORKSPACE);
        if (workspace != null && !workspace.trim().isEmpty()) {
            return Optional.of(new CIInfo() {
                @Override
                public String name() {
                    return NAME;

예를 들어 다음과 같은 `main.py` 파일이 있다고 합시다:

```Python hl_lines="3"
import os

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

/// tip | 팁

<a href="https://docs.python.org/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> 의 두 번째 인자는 반환할 기본값입니다.

여기서는 `"World"`를 넣었기에 기본값으로써 사용됩니다. 넣지 않으면 `None` 이 기본값으로 사용됩니다.

///

    public static final String NAME = "Generic";

    private static final String CI = "CI";

    @Override
    public Optional<CIInfo> detectCI() {
        String ciEnv = System.getenv(CI);
        if (ciEnv != null && !"false".equals(ciEnv)) {
            return Optional.of(new CIInfo() {
                @Override
                public String name() {
                    return NAME;
                }

	c.got = append(c.got, query)
	return c.db.QueryRowContext(ctx, query, args...)
}

func TestConnPoolWrapper(t *testing.T) {
	dialect := os.Getenv("GORM_DIALECT")
	if dialect != "mysql" {
		t.SkipNow()
	}

	dbDSN := os.Getenv("GORM_DSN")
	if dbDSN == "" {
		dbDSN = "gorm:gorm@tcp(localhost:9910)/gorm?charset=utf8&parseTime=True&loc=Local"
	}
	nativeDB, err := sql.Open("mysql", dbDSN)

例如，你可以创建一个名为 `main.py` 的文件，其中包含以下内容：

```Python hl_lines="3"
import os

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

/// tip

第二个参数是 <a href="https://docs.python.org/zh-cn/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> 的默认返回值。

如果没有提供，默认值为 `None`，这里我们提供 `"World"` 作为默认值。

///

然后你可以调用这个 Python 程序：

            if (envVars == null) {
                Properties tmp = new Properties();
                boolean caseSensitive = !Os.IS_WINDOWS;
                for (Map.Entry<String, String> entry : System.getenv().entrySet()) {
                    String key = "env."
                            + (caseSensitive ? entry.getKey() : entry.getKey().toUpperCase(Locale.ENGLISH));
                    tmp.setProperty(key, entry.getValue());