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** 🔜 🔘 🗜 ⚫️ 🔑 👨‍💼, & 🌀 ⚫️ ⏮️ 🎏 🔗 🧰.

			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
		}

		if f.ObjectSizeLessThan > 0 {

			},
		},
	}

	csvData := []byte(`one,two,three
-1,foo,true
,bar,false
2.5,baz,true
`)

	for i, testCase := range testTable {
		t.Run(fmt.Sprint(i), func(t *testing.T) {
			s3Select, err := NewS3Select(bytes.NewReader(testCase.requestXML))
			if err != nil {
				t.Fatal(err)
			}

			if err = s3Select.Open(newBytesRSC(csvData)); err != nil {

        .addEqualityGroup(wrapperFunction.apply(instance), wrapperFunction.apply(instance))
        .addEqualityGroup(wrapperFunction.apply(generator.newFreshProxy(interfaceType)))
        // TODO: add an overload to EqualsTester to print custom error message?
        .testEquals();
  }

  private static <T> void testToString(
      Class<T> interfaceType, Function<? super T, ? extends T> wrapperFunction) {

                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(() -> {

if net_len > 2000:
  start, end = 1000, 2000

[print(str(ip) + "/" + str(ip.max_prefixlen)) for ip in islice(ip_network('$CIDR').hosts(), start, end)]
EOF
}

function ips_to_cidrs() {
  IP_RANGE_START="$1"
  IP_RANGE_END="$2"
  python3 - <<EOF
from ipaddress import summarize_address_range, IPv4Address

```

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`

	// Get saved credentials.
	cred := globalActiveCred

	// Get saved region.
	region := globalSite.Region()

	apiEndpointStr := strings.TrimSpace(strings.Join(apiEndpoints, "  "))
	// Colorize the message and print.
	logger.Startup(color.Blue("API: ") + color.Bold(fmt.Sprintf("%s ", apiEndpointStr)))
	if color.IsTerminal() && (!globalServerCtxt.Anonymous && !globalServerCtxt.JSON && globalAPIConfig.permitRootAccess()) {

                        .filter(StringUtil::isNotBlank).orElse("-"));
        log(valueMap);
    }

    public void print(final String action, final OptionalThing<FessUserBean> user, final Map<String, String> params) {
        final Map<String, String> valueMap = new LinkedHashMap<>();