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 | 提示

第二个参数是 [`os.getenv()`](https://docs.python.org/3.8/library/os.html#os.getenv) 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：

//// tab | Linux, macOS, Windows Bash

    public static final String NAME = "TeamCity";

    private static final String TEAMCITY_VERSION = "TEAMCITY_VERSION";

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

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 [`os.getenv()`](https://docs.python.org/3.8/library/os.html#os.getenv) é o valor padrão a ser retornado.

Se não for fornecido, é `None` por padrão, Aqui fornecemos `"World"` como o valor padrão a ser usado.

func tidbSkip(t *testing.T, reason string) {
	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 mysqlVersionAtLeast(major, minor int) bool {
	if !isMysql() {
		return false
	}

	var version string

    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;
                }

    reportOnly.convention(false)
}

// TODO:isolated:incremental the service won't track up-to-date projects (project configuration skipped) that still run tests
if ("CI" in System.getenv() && project.name != "gradle-kotlin-dsl-accessors") {
    val testFilesCleanupServiceProvider = project.gradle.sharedServices.registerIfAbsent("testFilesCleanupBuildService", TestFilesCleanupService::class.java) {

	c.mustListObjects(ctx, lisaClient, "projectaorb")
	c.mustNotListObjects(ctx, lisaClient, "other")
}

func TestIAMWithOpenIDMultipleConfigsValidation1(t *testing.T) {
	openIDServer := os.Getenv(EnvTestOpenIDServer)
	openIDServer2 := os.Getenv(EnvTestOpenIDServer2)
	if openIDServer == "" || openIDServer2 == "" {
		t.Skip("Skipping OpenID test as enough OpenID servers are not provided.")
	}
	testApps := testClientApps

	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)

func (c *Config) ApplyEnv() {
	configLock.RLock()
	defer configLock.RUnlock()

	if c.License != "" {
		os.Setenv("CONSOLE_SUBNET_LICENSE", c.License)
	}
	if c.APIKey != "" {
		os.Setenv("CONSOLE_SUBNET_API_KEY", c.APIKey)
	}
	if c.Proxy != "" {
		os.Setenv("CONSOLE_SUBNET_PROXY", c.Proxy)
	}
	os.Setenv("CONSOLE_SUBNET_URL", c.BaseURL)
}

// Update - in-place update with new license and registration information.

    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;
                }