}

	// The following block will create a bucket policy with delete object to 'public/*'. This is
	// to test a mixed response of a successful & failure while deleting objects in a single request
	policyBytes := []byte(fmt.Sprintf(`{"Id": "Policy1637752602639", "Version": "2012-10-17", "Statement": [{"Sid": "Stmt1637752600730", "Action": "s3:DeleteObject", "Effect": "Allow", "Resource": "arn:aws:s3:::%s/public/*", "Principal": "*"}]}`, bucketName))

		if err != nil {
			writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
			return
		}
		copy(objectEncryptionKey[:], key)

		var nonce [12]byte
		tmp := sha256.Sum256([]byte(fmt.Sprint(uploadID, partID)))
		copy(nonce[:], tmp[:12])

		partEncryptionKey := objectEncryptionKey.DerivePartKey(uint32(partID))
		encReader, err := sio.EncryptReader(reader, sio.Config{
			Key:          partEncryptionKey[:],

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

Underneath, the `open("./somefile.txt")` creates an object that is called a "Context Manager".

When the `with` block finishes, it makes sure to close the file, even if there were exceptions.

		if deploymentID != formats[i].ID {
			return nil, fmt.Errorf("all pools must have same deployment ID - expected %s, got %s for pool(%s)", deploymentID, formats[i].ID, humanize.Ordinal(i+1))
		}

		bootstrapTrace(fmt.Sprintf("newErasureSets: initializing %s pool", humanize.Ordinal(i+1)), func() {
			z.serverPools[i], err = newErasureSets(ctx, ep, storageDisks[i], formats[i], commonParityDrives, i)
		})
		if err != nil {
			return nil, err

			}
			return written, nil
		}
	}
}

// SafeClose safely closes any channel of any type
func SafeClose[T any](c chan<- T) {
	if c != nil {
		close(c)
		return
	}
	// Print stack to check who is sending `c` as `nil`
	// without crashing the server.
	debug.PrintStack()

```

そして呼び出すと:

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

これで変数`user_dict`のデータを持つ`dict`ができました。（これはPydanticモデルのオブジェクトの代わりに`dict`です）。

そして呼び出すと:

```Python
print(user_dict)
```

以下のようなPythonの`dict`を得ることができます:

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

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

在底层，`open("./somefile.txt")`创建了一个被称为"上下文管理器"的对象。

当 `with` 代码块结束时，它会确保关闭文件，即使发生了异常也是如此。

当你使用 `yield` 创建一个依赖项时，**FastAPI** 会在内部将其转换为上下文管理器，并与其他相关工具结合使用。

### 在使用 `yield` 的依赖项中使用上下文管理器

</div>

////

### ✍ 🇨🇻 {🐍

👆 💪 ✍ 🌐 🔢 🏞 🐍, 📶 (⚖️ ⏮️ 🙆 🎏 👩‍🔬), &amp; ⤴️ ✍ 👫 🐍.

🖼 👆 💪 ✔️ 📁 `main.py` ⏮️:

```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> 🔢 💲 📨.

-flexbox!important;display:inline-flex!important}}@media print{.d-print-none{display:none!important}.d-print-inline{display:inline!important}.d-print-inline-block{display:inline-block!important}.d-print-block{display:block!important}.d-print-table{display:table!important}.d-print-table-row{display:table-row!important}.d-print-table-cell{display:table-cell!important}.d-print-flex{display:-ms-flexbox!important;display:flex!important}.d-print-inline-flex{display:-ms-inline-flexbox!important;display...

		{"192.168.1.210:9000", Endpoint{}, -1, fmt.Errorf("invalid URL endpoint format: missing scheme http or https")},
	}

	for i, test := range testCases {
		t.Run(fmt.Sprint("case-", i), func(t *testing.T) {
			endpoint, err := NewEndpoint(test.arg)
			if err == nil {
				err = endpoint.UpdateIsLocal()
			}

			switch {
			case test.expectedErr == nil:
				if err != nil {