{* ../../docs_src/settings/app02_an_py310/test_main.py hl[9:10,13,21] *}

在依赖项覆盖中，我们在创建新的 `Settings` 对象时为 `admin_email` 设置了一个新值，然后返回该新对象。

然后我们可以测试它是否被使用。

## 读取 `.env` 文件 { #reading-a-env-file }

如果你有许多设置可能经常变化，或在不同环境中不同，那么把它们放进一个文件中，然后像环境变量一样从中读取，可能非常有用。

这种做法非常常见：这些环境变量通常放在名为 `.env` 的文件中，该文件被称为 “dotenv”。

/// tip | 提示

以点（`.`）开头的文件在类 Unix 系统（如 Linux 和 macOS）中是隐藏文件。

		// Buffer size greater than object size. - 6
		{
			volume, "myobject", 0, 16,
			[]byte("hello, world"),
			io.ErrUnexpectedEOF,
		},
		// Reading from an offset success. - 7
		{
			volume, "myobject", 7, 5,
			[]byte("world"), nil,
		},
		// Reading from an object but buffer size greater. - 8
		{
			volume, "myobject",
			7, 8,
			[]byte("world"),
			io.ErrUnexpectedEOF,
		},

// license that can be found in the LICENSE file.

package bufio

import (
	"bytes"
	"errors"
	"io"
	"unicode/utf8"
)

// Scanner provides a convenient interface for reading data such as
// a file of newline-delimited lines of text. Successive calls to
// the [Scanner.Scan] method will step through the 'tokens' of a file, skipping
// the bytes between the tokens. The specification of a token is

        final Map<String, Object> secondLine = new HashMap<>();

        secondLine.put("text", item.getText());

        // reading
        final String[][] readings = item.getReadings();
        for (int i = 0; i < readings.length; i++) {
            secondLine.put("reading_" + i, readings[i]);
        }

        secondLine.put("fields", item.getFields());
        secondLine.put("queryFreq", item.getQueryFreq());

    valueSetCapacity = DEFAULT_VALUE_SET_CAPACITY;
    int distinctKeys = stream.readInt();
    Map<K, Collection<V>> map = Platform.newLinkedHashMapWithExpectedSize(12);
    for (int i = 0; i < distinctKeys; i++) {
      @SuppressWarnings("unchecked")
      K key = (K) stream.readObject();
      map.put(key, createCollection(key));
    }
    int entries = stream.readInt();
    for (int i = 0; i < entries; i++) {

## 情境管理器 { #context-managers }

### 什麼是「情境管理器」 { #what-are-context-managers }

「情境管理器」是那些你可以在 `with` 陳述式中使用的 Python 物件。

例如，[你可以用 `with` 來讀取檔案](https://docs.python.org/3/tutorial/inputoutput.html#reading-and-writing-files)：

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

在底層，`open("./somefile.txt")` 會建立一個稱為「情境管理器」的物件。

    return {};
  }
  const auto& fdef_lib = gdef.library();
  if (fdef_lib.gradient_size() > 0) {
    status->status = tensorflow::errors::Internal(
        "GradientDef is not supported in reading Dataset related functions: ",
        text_proto);
    return {};
  }
  std::vector<UniqueFuncPtr> ret;
  for (const FunctionDef& fdef : fdef_lib.function()) {
    // Make a copy so that we can mutate it.

		}
	}

	contentBytes, err := io.ReadAll(resp.Body)
	if err != nil {
		return content, AdminError{
			Code:       AdminUpdateUnexpectedFailure,
			Message:    fmt.Sprintf("Error reading response. %s", err),
			StatusCode: http.StatusInternalServerError,
		}
	}

	return string(contentBytes), nil
}

func releaseInfoToReleaseTime(releaseInfo string) (releaseTime time.Time, err error) {

   * the traverser cannot guarantee that it will not follow symbolic links to directories as it is
   * possible for a directory to be replaced with a symbolic link between checking if the file is a
   * directory and actually reading the contents of that directory.
   *
   * <p>If the {@link Path} passed to one of the traversal methods does not exist or is not a
   * directory, no exception will be thrown and the returned {@link Iterable} will contain a single

Hallo wieder
////

### Headings

Every Markdown heading in the English text (all levels) ends with a part inside curly brackets. This part denotes the hash of this heading, which is used in links to this heading. In translations, translate the heading, but do not translate this hash part, so that links do not break.

Examples of how to translate a heading:

Source (English):

```