return err
		}
	case !f.Tag.IsEmpty():
		if err := e.EncodeElement(f.Tag, xml.StartElement{Name: xml.Name{Local: "Tag"}}); err != nil {
			return err
		}
	default:
		// Always print Prefix field when both And & Tag are empty
		if err := e.EncodeElement(f.Prefix, xml.StartElement{Name: xml.Name{Local: "Prefix"}}); err != nil {
			return err
		}
	}

pure_python_whl=$(basename "${pure_python_whl}")

# Extract the package name from the wheel name. That is, extract every character
# before the pattern "-py3-" in the wheel name.
pkg_name=$(echo "${pure_python_whl}" | awk -F'-py3-' '{print $1}')

# Save the current working directory and then switch to the output directory.
pushd "${TFCI_OUTPUT_DIR}"

# Unpack the wheel to get all the file contents. The pure python wheel we built

supports both synchronous blocking calls and async calls with callbacks.


Get a URL
---------

This program downloads a URL and prints its contents as a string. [Full source][get_example].

```java
OkHttpClient client = new OkHttpClient();

String run(String url) throws IOException {
  Request request = new Request.Builder()
      .url(url)

		namespace, serviceAccount, kubeClient, multixds.DefaultOptions)
	if respErr != nil {
		return xdsResponses, respErr
	}
	_, _ = fmt.Fprint(writer, "error: according to below command list, please check all supported internal debug commands\n")
	return xdsResponses, nil
}

func HandlerForDebugErrors(kubeClient kube.CLIClient,

# If we are not using the default, assume its private and we need to authenticate
if [[ "${ISTIO_ENVOY_BASE_URL}" != "https://storage.googleapis.com/istio-build/proxy" ]]; then
  AUTH_HEADER="Authorization: Bearer $(gcloud auth print-access-token)"
  export AUTH_HEADER
fi

SIDECAR="${SIDECAR:-envoy}"

# OS-neutral vars. These currently only work for linux.
ISTIO_ENVOY_VERSION="${ISTIO_ENVOY_VERSION:-${PROXY_REPO_SHA}}"

Je kunt bijvoorbeeld een bestand `main.py` hebben met:

```Python hl_lines="3"
import os

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

/// tip

For example you could have a file `main.py` with:

```Python hl_lines="3"
import os

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

/// tip

The second argument to <a href="https://docs.python.org/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> is the default value to return.

```Python
with open("./somefile.txt") as f:
    contents = f.read()
    print(contents)
```

🔘, `open("./somefile.txt")` ✍ 🎚 👈 🤙 "🔑 👨‍💼".

🕐❔ `with` 🍫 🏁, ⚫️ ⚒ 💭 🔐 📁, 🚥 📤 ⚠.

🕐❔ 👆 ✍ 🔗 ⏮️ `yield`, **FastAPI** 🔜 🔘 🗜 ⚫️ 🔑 👨‍💼, & 🌀 ⚫️ ⏮️ 🎏 🔗 🧰.

                saveInfo(messages -> messages.addSuccessPrintThreadDump(GLOBAL));
            } catch (final Exception e) {
                logger.warn("Failed to print a thread dump.", e);
                throwValidationError(messages -> messages.addErrorsFailedToPrintThreadDump(GLOBAL), this::asListHtml);
            }
        }).orElse(() -> {

```

就能以如下方式调用：

```Python
user_dict = user_in.dict()
```

现在，变量 `user_dict`中的就是包含数据的**字典**（变量 `user_dict` 是字典，不是 Pydantic 模型对象）。

以如下方式调用：

```Python
print(user_dict)
```

输出的就是 Python **字典**：

```Python
{
    'username': 'john',
    'password': 'secret',
    'email': '******@****.***',
    'full_name': None,
}
```

#### 解包 `dict`