例如，您可以有一个名为 `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

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

如果没有提供默认值，默认为 `None`，此处我们提供了 `"World"` 作为要使用的默认值。

///

然后，您可以调用该 Python 程序：

<div class="termy">

```Python hl_lines="4  21"
{!> ../../docs_src/encoder/tutorial001_py310.py!}
```

////

👉 🖼, ⚫️ 🔜 🗜 Pydantic 🏷 `dict`, & `datetime` `str`.

🏁 🤙 ⚫️ 🕳 👈 💪 🗜 ⏮️ 🐍 🐩 <a href="https://docs.python.org/3/library/json.html#json.dumps" class="external-link" target="_blank">`json.dumps()`</a>.

⚫️ 🚫 📨 ⭕ `str` ⚗ 💽 🎻 📁 (🎻). ⚫️ 📨 🐍 🐩 💽 📊 (✅ `dict`) ⏮️ 💲 &amp; 🎧-💲 👈 🌐 🔗 ⏮️ 🎻.

/// note

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package gradlebuild.docs

import org.w3c.dom.Document
import org.w3c.dom.Element
import org.w3c.dom.Node
import org.w3c.dom.NodeList

class DomBuilder extends BuilderSupport {
    Document document
    Node parent

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package gradlebuild.docs.dsl.source.model;

import org.gradle.api.Transformer;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;

# Custom Response Classes - File, HTML, Redirect, Streaming, etc.

There are several custom response classes you can use to create an instance and return them directly from your *path operations*.

Read more about it in the [FastAPI docs for Custom Response - HTML, Stream, File, others](https://fastapi.tiangolo.com/advanced/custom-response/).

You can import them directly from `fastapi.responses`:

```python
from fastapi.responses import (
    FileResponse,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package gradlebuild.docs.dsl.docbook;

import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import java.util.ArrayList;
import java.util.List;

public class ModelBuilderSupport {

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package gradlebuild.docs;

import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.stream.StreamResult;

 <font color="#4E9A06">│  Serving at: http://0.0.0.0:8000                    │</font>
 <font color="#4E9A06">│                                                     │</font>
 <font color="#4E9A06">│  API docs: http://0.0.0.0:8000/docs                 │</font>
 <font color="#4E9A06">│                                                     │</font>
 <font color="#4E9A06">│  Running in production mode, for development use:   │</font>

	printEventNotifiers()
	printLambdaTargets()
}

// Prints startup message for Object API access, prints link to our SDK documentation.
func printObjectAPIMsg() {
	logger.Startup(color.Blue("\nDocs: ") + "https://docs.min.io")
}

func printLambdaTargets() {
	if globalLambdaTargetList == nil || globalLambdaTargetList.Empty() {
		return
	}

	arnMsg := color.Blue("Object Lambda ARNs: ")

## Caveat

If you need to perform heavy background computation and you don't necessarily need it to be run by the same process (for example, you don't need to share memory, variables, etc), you might benefit from using other bigger tools like <a href="https://docs.celeryq.dev" class="external-link" target="_blank">Celery</a>.