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 [`os.getenv()`](https://docs.python.org/3.8/library/os.html#os.getenv) 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：

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

<div class="termy">

# Code blocks { #code-blocks }

Some text

```python
# This is a sample Python code block
def hello_world():
    # Comment with indentation
    print("Hello, world!")  # Print greeting
```

Some more text

```toml
# This is a sample TOML code block
title = "TOML Example"  # Title of the document
```

And more text

```console
// Use the command "live" and pass the language code as a CLI argument

# Code blocks { #code-blocks }

Some text

```python
# This is a sample Python code block
def hello_world():
    # Comment with indentation
    print("Hello, world!")  # Print greeting
```

Some more text

```toml
# This is a sample TOML code block
title = "TOML Example"  # Title of the document
```

Extra code block

```
$ cd my_project
```

And more text

```console

Якщо ви запустите це й перейдете на [http://localhost:8000/v1/](http://localhost:8000/v1/), ви побачите відповідь від Flask:

```txt
Hello, World from Flask!
```

А якщо ви перейдете на [http://localhost:8000/v2](http://localhost:8000/v2), ви побачите відповідь від FastAPI:

```JSON
{
    "message": "Hello World"
}

```Python hl_lines="3"
import os

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

/// tip | Tipp

Das zweite Argument von [`os.getenv()`](https://docs.python.org/3.8/library/os.html#os.getenv) ist der Defaultwert, der zurückgegeben wird.

Wenn er nicht angegeben wird, ist er standardmäßig `None`. Hier geben wir „World“ als den zu verwendenden Defaultwert an.

///

	Name4        string `gorm:"uniqueIndex"`
	Name5        int64  `gorm:"index:,class:FULLTEXT,comment:hello \\, world,where:age > 10"`
	Name6        int64  `gorm:"index:profile,comment:hello \\, world,where:age > 10"`
	Age          int64  `gorm:"index:profile,expression:ABS(age),option:WITH PARSER parser_name"`
	OID          int64  `gorm:"index:idx_id;index:idx_oid,unique"`

    /** */
    public int intField;

    /** */
    public String stringField;

    /** */
    public static final int INT_DATA = 987654321;

    /** */
    public static final String STRING_DATA = "Hello World!";

    /**
     * @throws Exception
     */
    @Test
    public void testGet() throws Exception {
        final Field field = getClass().getField("objectField");

Si lo ejecutas y vas a [http://localhost:8000/v1/](http://localhost:8000/v1/) verás el response de Flask:

```txt
Hello, World from Flask!
```

Y si vas a [http://localhost:8000/v2](http://localhost:8000/v2) verás el response de FastAPI:

```JSON
{
    "message": "Hello World"
}

```Python hl_lines="3"
import os

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

/// tip

The second argument to [`os.getenv()`](https://docs.python.org/3.8/library/os.html#os.getenv) is the default value to return.

If not provided, it's `None` by default, here we provide `"World"` as the default value to use.

///

Then you could call that Python program:

```Python hl_lines="3"
import os

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

/// tip | Astuce

Le deuxième argument de [`os.getenv()`](https://docs.python.org/3.8/library/os.html#os.getenv) est la valeur par défaut à retourner.

S'il n'est pas fourni, c'est `None` par défaut ; ici, nous fournissons `"World"` comme valeur par défaut à utiliser.

///