Например, у вас есть файл `main.py`:

```Python hl_lines="3"
import os

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

/// tip | Совет

Второй аргумент <a href="https://docs.python.org/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> - это возвращаемое по умолчанию значение.

//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package mountinfo

import (
	"fmt"
	"os"
	"path/filepath"
	"strings"
	"testing"
)

// Tests cross device mount verification function, for both failure
// and success cases.
func TestCrossDeviceMountPaths(t *testing.T) {

					// and check if that disk
					// appears in outDatedDisks.
					tamperedIndex = index
					filePath := pathJoin(erasureDisks[index].String(), bucket, object, fi.DataDir, "part.1")
					f, err := os.OpenFile(filePath, os.O_WRONLY|os.O_SYNC, 0)
					if err != nil {
						t.Fatalf("Failed to open %s: %s\n", filePath, err)
					}
					f.WriteString("oops") // Will cause bitrot error
					f.Close()
					break
				}
			}

}

fun Test.addOsAsInputs() {
    // Add OS as inputs since tests on different OS may behave differently https://github.com/gradle/gradle-private/issues/2831
    // the version currently differs between our dev infrastructure, so we only track the name and the architecture
    inputs.property("operatingSystem", "${OperatingSystem.current().name} ${System.getProperty("os.arch")}")
}

//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

import (
	"context"
	"os"
	"reflect"
	"sync"
	"testing"

	"github.com/minio/minio/internal/dsync"
)

// Helper function to create a lock server for testing

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

import (
	"os"
	"syscall"
)

var (
	// Disallow updating access times
	// Add non-block to avoid syscall to attempt to set epoll on files.
	readMode = os.O_RDONLY | 0x40000 | syscall.O_NONBLOCK // O_NOATIME

	// Write with data sync only used only for `xl.meta` writes

例如，你可以建立一個名為 `main.py` 的檔案，其中包含以下內容：

```Python hl_lines="3"
import os

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

/// tip

第二個參數是 <a href="https://docs.python.org/zh-tw/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> 的預設回傳值。

如果沒有提供，預設值為 `None`，這裡我們提供 `"World"` 作為預設值。

///

然後你可以呼叫這個 Python 程式：

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package asm

import (
	"bufio"
	"bytes"
	"fmt"
	"internal/buildcfg"
	"os"
	"path/filepath"
	"regexp"
	"sort"
	"strconv"
	"strings"
	"testing"

	"cmd/asm/internal/lex"
	"cmd/internal/obj"
)

// An end-to-end test for the assembler: Do we print what we parse?

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

import (
	"bufio"
	"crypto"
	"crypto/tls"
	"encoding/hex"
	"errors"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"os"
	"path"
	"path/filepath"
	"runtime"
	"strings"
	"sync/atomic"
	"time"

	"github.com/klauspost/compress/zstd"
	xhttp "github.com/minio/minio/internal/http"
	"github.com/minio/minio/internal/logger"

**Expected behavior**
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**Screenshots**
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**Environment (please complete the following information):**
 - OS: [e.g. Windows 10]
 - Browser [e.g. chrome, safari]
 - Version [e.g. 13.5.0]

**Additional context**