public final Optional<@NonNull E> first() {
    Iterator<E> iterator = getDelegate().iterator();
    return iterator.hasNext() ? Optional.of(iterator.next()) : Optional.absent();
  }

  /**
   * Returns an {@link Optional} containing the last element in this fluent iterable. If the
   * iterable is empty, {@code Optional.absent()} is returned. If the underlying {@code iterable} is

    }

    @Override
    public Optional<Long> sizeIfKnown() {
      Optional<Long> optionalUnslicedSize = ByteSource.this.sizeIfKnown();
      if (optionalUnslicedSize.isPresent()) {
        long unslicedSize = optionalUnslicedSize.get();
        long off = min(offset, unslicedSize);
        return Optional.of(min(length, unslicedSize - off));
      }
      return Optional.absent();
    }

    @Override

     *
     * @param dir the directory to locate the pom for, never {@code null}
     * @param options possible parsing options, may be {@code null}
     * @return an optional parsed {@link Model} or {@code null} if none could be found
     * @throws ModelParserException if the located model cannot be parsed
     */
    @Nonnull

import org.codelibs.fess.util.ComponentUtil;
import org.codelibs.fess.util.DocumentUtil;
import org.codelibs.fess.util.FacetResponse;
import org.dbflute.optional.OptionalEntity;
import org.dbflute.optional.OptionalThing;
import org.lastaflute.web.util.LaRequestUtil;
import org.opensearch.action.search.SearchRequestBuilder;
import org.opensearch.action.search.SearchResponse;

# Apache Maven Encrypt Script
#
# Environment Variable Prerequisites
#
#   JAVA_HOME           (Optional) Points to a Java installation.
#   MAVEN_OPTS          (Optional) Java runtime options used when Maven is executed.
#   MAVEN_SKIP_RC       (Optional) Flag to disable loading of mavenrc files.
# -----------------------------------------------------------------------------

# Apache Maven Encrypt Script
#
# Environment Variable Prerequisites
#
#   JAVA_HOME           (Optional) Points to a Java installation.
#   MAVEN_OPTS          (Optional) Java runtime options used when Maven is executed.
#   MAVEN_SKIP_RC       (Optional) Flag to disable loading of mavenrc files.
# -----------------------------------------------------------------------------

توی پایتون 3.6 و بالاتر (از جمله پایتون 3.10) می‌تونی با وارد کردن و استفاده از `Optional` از ماژول `typing` اینو تعریف کنی.

```Python hl_lines="1  4"
{!../../docs_src/python_types/tutorial009.py!}
```

استفاده از `Optional[str]` به جای فقط `str` به ویرایشگر کمک می‌کنه خطاهایی که ممکنه فکر کنی یه مقدار همیشه `str` هست رو پیدا کنه، در حالی که می‌تونه `None` هم باشه.

  ElementOrder<N> nodeOrder = ElementOrder.insertion();
  ElementOrder<N> incidentEdgeOrder = ElementOrder.unordered();

  Optional<Integer> expectedNodeCount = Optional.absent();

  /**
   * Creates a new instance with the specified edge directionality.
   *
   * @param directed if true, creates an instance for graphs whose edges are each directed; if
   *     false, creates an instance for graphs whose edges are each undirected.
   */

 */
package org.apache.maven.api.services;

import java.io.Closeable;
import java.net.URI;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.nio.file.Path;
import java.util.Optional;

import org.apache.maven.api.RemoteRepository;
import org.apache.maven.api.annotations.Consumer;
import org.apache.maven.api.annotations.Experimental;
import org.apache.maven.api.annotations.Nonnull;

/**

            }

            @Nonnull
            @Override
            public Optional<Project> getProject() {
                return Optional.ofNullable(project);
            }

            @Nonnull
            @Override
            public Optional<Artifact> getRootArtifact() {
                return Optional.ofNullable(rootArtifact);
            }

            @Nonnull
            @Override