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

Por baixo dos panos, o código `open("./somefile.txt")` cria um objeto que é chamado de "Gerenciador de Contexto".

Quando o bloco `with` finaliza, ele se certifica de fechar o arquivo, mesmo que tenha ocorrido alguma exceção.

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

import (
	"context"
	"net/http"
	"net/url"
)

// Writes S3 compatible copy part range error.
func writeCopyPartErr(ctx context.Context, w http.ResponseWriter, err error, url *url.URL) {
	switch err {
	case errInvalidRange:

package proxyconfig

import (
	"context"
	"encoding/json"
	"fmt"
	"io"
	"text/tabwriter"

	"github.com/spf13/cobra"

	"istio.io/istio/istioctl/pkg/cli"
	"istio.io/istio/istioctl/pkg/clioptions"
	"istio.io/istio/pkg/cluster"
)

// TODO move to multicluster package; requires exposing some private funcs/vars in this package
func ClustersCommand(ctx cli.Context) *cobra.Command {

    @SuppressWarnings("unchecked")
    public void execute(ViolationCheckContextWithViolations context) {
        Set<AccessorKey> seenUpgradedAccessorsChanges = (Set<AccessorKey>) context.getUserData().get(SEEN_OLD_REMOVED_ACCESSORS_OF_UPGRADED_PROPERTIES);
        Map<AccessorKey, ReplacedAccessor> oldAccessorsOfUpgradedProperties = (Map<AccessorKey, ReplacedAccessor>) context.getUserData().get(OLD_REMOVED_ACCESSORS_OF_UPGRADED_PROPERTIES);

	cachesRoot map[string][]string `msg:"-"`

	// Internal state
	mu      sync.RWMutex `msg:"-"`
	updated bool         `msg:"-"`
}

type deleteAllStorager interface {
	deleteAll(ctx context.Context, bucket, prefix string)
}

// newBucketMetacache creates a new bucketMetacache.
// Optionally remove all existing caches.
func newBucketMetacache(bucket string, cleanup bool) *bucketMetacache {
	if cleanup {

//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

//go:generate msgp -file=$GOFILE

package cmd

import (
	"context"
	"encoding/binary"
	"errors"
	"fmt"
	"io"
	"sync"
	"sync/atomic"
	"time"

	"github.com/google/uuid"
	"github.com/minio/madmin-go/v3"
	"github.com/minio/pkg/v3/wildcard"

     */
    public static boolean shouldAcceptForUpgradedProperty(JApiMethod jApiMethod, Violation violation, ViolationCheckContext context) {
        Map<AccessorKey, UpgradedProperty> currentAccessors = context.getUserData(CURRENT_ACCESSORS_OF_UPGRADED_PROPERTIES);
        Map<AccessorKey, ReplacedAccessor> oldRemovedAccessors = context.getUserData(OLD_REMOVED_ACCESSORS_OF_UPGRADED_PROPERTIES);

     * public static String getDomainByName(String name) throws UnknownHostException {
     * DirContext context;
     * UnknownHostException uhe = null;
     * 
     * try {
     * context = new InitialDirContext();
     * for ( ;; ) {
     * try {
     * Attributes attributes = context.getAttributes(
     * "dns:/_ldap._tcp.dc._msdcs." + name,
     * new String[] { "SRV" }
     * );
     * return name;

 * </pre>
 * 
 * </td>
 * <td>
 * Open the Named Pipe foo for reading and writing. The pipe will behave like the <code>CallNamedPipe</code> interface.
 * </td>
 * </tr>
 * <tr>
 * <td width="20%">
 * 
 * <pre>
 * new SmbNamedPipe("smb://server/IPC$/foo", SmbNamedPipe.PIPE_TYPE_RDWR | SmbNamedPipe.PIPE_TYPE_TRANSACT, context);
 * </pre>
 * 
 * </td>
 * <td>

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import jcifs.context.SingletonContext;


/**
 * This class now contains only utilities for config parsing.
 * 
 * We strongly suggest that you create an explicit {@link jcifs.context.CIFSContextWrapper}
 * with your desired config. It's base implementation {@link jcifs.context.BaseContext}
 * should be sufficient for most needs.
 *