例如，<a href="https://docs.python.org/zh-cn/3/tutorial/inputoutput.html#reading-and-writing-files" class="external-link" target="_blank">你可以使用`with`读取文件</a>：

```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。

    /**
     * Merges the specified source object into the given target object.
     *
     * @param target The target object whose existing contents should be merged with the source, must not be
     *            <code>null</code>.
     * @param source The (read-only) source object that should be merged into the target object, may be
     *            <code>null</code>.

    if (entries.size() >= 1) {
      a = entries.get(0);
      if (entries.size() >= 3) {
        b = entries.get(1);
        c = entries.get(2);
      }
    }
  }

  /** Resets the contents of navigableMap to have entries a, c, for the navigation tests. */
  @SuppressWarnings("unchecked") // Needed to stop Eclipse whining
  private void resetWithHole() {

/**
 * Exception which occurs when a normal (i.e. non-aggregator) mojo fails to
 * execute. In this case, the mojo failed while executing against a particular
 * project instance, so we can wrap the {@link MojoFailureException} with context
 * information including projectId that caused the failure.
 *
 *
 */
public class ProjectBuildFailureException extends BuildFailureException {

    private final String projectId;

package hash

import (
	"bytes"
	"context"
	"crypto/sha1"
	"encoding/base64"
	"encoding/binary"
	"fmt"
	"hash"
	"hash/crc32"
	"net/http"
	"strconv"
	"strings"

	"github.com/minio/minio/internal/hash/sha256"
	xhttp "github.com/minio/minio/internal/http"
	"github.com/minio/minio/internal/logger"
)

func hashLogIf(ctx context.Context, err error) {
	logger.LogIf(ctx, "hash", err)
}

	opts := &GenerateOptions{
		Generate: generate,
		Tag:      "default",
		Revision: "default",
	}

	_, err := Generate(context.TODO(), fakeClient, opts, "istio-system")
	assert.NoError(t, err)

	wh, err := fakeClient.Kube().AdmissionregistrationV1().MutatingWebhookConfigurations().
		Get(context.Background(), "istio-sidecar-injector", metav1.GetOptions{})
	assert.NoError(t, err)

	assertFunc(t, wh.Webhooks, defaultWh.Webhooks)

	"github.com/minio/pkg/v3/env"
	xnet "github.com/minio/pkg/v3/net"
)

const (
	formatNamespace = "namespace"
)

const (
	logSubsys = "notify"
)

func logOnceIf(ctx context.Context, err error, id string, errKind ...interface{}) {
	logger.LogOnceIf(ctx, logSubsys, err, id, errKind...)
}

// ErrTargetsOffline - Indicates single/multiple target failures.

import java.util.HashMap;
import java.util.Map;

import org.apache.maven.eventspy.EventSpy;

/**
 * DefaultEventSpyContext
 */
public class DefaultEventSpyContext implements EventSpy.Context {

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

    public Map<String, Object> getData() {
        return data;
    }

By creating this pull request I represent that I have the right to license the 
contributions to the project maintainers under the Apache 2 license.

## Description


## Motivation and Context


## How to test this PR?


## Types of changes
- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)

* `close()`: 🔐 📁.

🌐 👫 👩‍🔬 `async` 👩‍🔬, 👆 💪 "⌛" 👫.

🖼, 🔘 `async` *➡ 🛠️ 🔢* 👆 💪 🤚 🎚 ⏮️:

```Python
contents = await myfile.read()
```

🚥 👆 🔘 😐 `def` *➡ 🛠️ 🔢*, 👆 💪 🔐 `UploadFile.file` 🔗, 🖼:

```Python
contents = myfile.file.read()
```

/// note | "`async` 📡 ℹ"

🕐❔ 👆 ⚙️ `async` 👩‍🔬, **FastAPI** 🏃 📁 👩‍🔬 🧵 & ⌛ 👫.

///