* {@code Optional.orElse(null)}.
   */
  public abstract @Nullable T orNull();

  /**
   * Returns an immutable singleton {@link Set} whose only element is the contained instance if it
   * is present; an empty immutable {@link Set} otherwise.
   *
   * <p><b>Comparison to {@code java.util.Optional}:</b> this method has no equivalent in Java 8's
   * {@code Optional} class. However, this common usage:

    /**
     * Gets the expiration time for thumbnails.
     *
     * @return the expiration time in milliseconds
     */
    public long getExpiry() {
        return expiry;
    }

    /**
     * Sets the expiration time for thumbnails.
     *
     * @param expiry the expiration time in milliseconds (must be positive)
     * @return this PurgeThumbnailJob instance for method chaining
     */

마찬가지로 예제에서 `tags`를 구체적으로 "문자열의 리스트"로 만들 수 있습니다:

{* ../../docs_src/body_nested_models/tutorial002_py310.py hl[12] *}

## 집합 타입 { #set-types }

그런데 생각해보니 태그는 반복되면 안 되고, 아마 고유한 문자열이어야 할 것입니다.

그리고 파이썬에는 고유한 항목들의 집합을 위한 특별한 데이터 타입 `set`이 있습니다.

그렇다면 `tags`를 문자열의 집합으로 선언할 수 있습니다:

{* ../../docs_src/body_nested_models/tutorial003_py310.py hl[12] *}

이렇게 하면 중복 데이터가 있는 요청을 받더라도 고유한 항목들의 집합으로 변환됩니다.

import com.google.common.collect.testing.TestSubjectGenerator;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Derived suite generators for Guava collection interfaces, split out of the suite builders so that
 * they are available to GWT.

                                           TF_Status* s);

// Create an operation suitable to use with the provided context. The operation
// requires its type (e.g. "AddV2") to be set independently.
TF_AbstractOp* TF_NewAbstractOp(TF_ExecutionContext* ctx);
void TF_DeleteAbstractOp(TF_AbstractOp*);

// TODO(srbs): Add APIs for specifying attrs etc.
// `op_type` must outlive `op`.

            SourceSet mainSourceSet = GradleUtils.getJavaSourceSets(project).findByName(SourceSet.MAIN_SOURCE_SET_NAME);
            t.getSrcDirs().set(project.provider(() -> mainSourceSet.getAllSource().getSrcDirs()));
        });
        return task;
    }

    - "*.x"
  workflow_dispatch:

jobs:
  build:
    runs-on: ubuntu-24.04
    env:
      PARENT_BRANCH: main
    timeout-minutes: 15
    steps:
    - uses: actions/checkout@v4
    - name: Set up JDK 21
      uses: actions/setup-java@v4
      with:
        java-version: '21'
        distribution: 'temurin'
    - uses: actions/cache@v4
      with:
        path: ~/.m2/repository

internal fun buildCache(
  file: Path,
  maxSize: Long,
  fileSystem: FileSystem,
): Cache = Cache(fileSystem, file, maxSize)

internal var RealConnection.idleAtNsAccessor: Long
  get() = idleAtNs
  set(value) {
    idleAtNs = value
  }

internal val Response.exchangeAccessor: Exchange?
  get() = this.exchange

internal val Exchange.connectionAccessor: RealConnection
  get() = this.connection

 *   <li>These tests are "conformance tests", and do not attempt to test throughput, latency,
 *       scalability or other performance factors (see the separate "jtreg" tests for a set intended
 *       to check these for the most central aspects of functionality.) So, most tests use the
 *       smallest sensible numbers of threads, collection sizes, etc needed to check basic
 *       conformance.

     */
    public void delete(final RoleType roleType) {

        roleTypeBhv.delete(roleType, op -> {
            op.setRefreshPolicy(Constants.TRUE);
        });

    }

    /**
     * Sets up the list condition for the role type query.
     * @param cb The role type condition bean.
     * @param roleTypePager The role type pager.
     */