/** Puts all the associations from {@code rangeMap} into this range map (optional operation). */
  void putAll(RangeMap<K, ? extends V> rangeMap);

  /** Removes all associations from this range map (optional operation). */
  void clear();

  /**
   * Removes all associations from this range map in the specified range (optional operation).
   *

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.api.services;

import java.util.List;
import java.util.Optional;

import org.apache.maven.api.Repository;
import org.apache.maven.api.Version;
import org.apache.maven.api.annotations.Experimental;
import org.apache.maven.api.annotations.Nonnull;

/**
 *
 * @since 4.0.0

                    }
                }

                @Nonnull
                @Override
                public Optional<org.apache.maven.api.Toolchain> createDefaultToolchain()
                        throws ToolchainFactoryException {
                    return Optional.ofNullable(v3Factory.createDefaultToolchain())
                            .map(ToolchainManagerFactory.this::getToolchainV4);
                }

     *
     * @see Function
     * @see Optional
     * @see HashMap#computeIfAbsent(Object, Function)
     */
    static UnaryOperator<String> memoize(UnaryOperator<String> callback) {
        Map<String, Optional<String>> cache = new HashMap<>();
        return s -> cache.computeIfAbsent(s, v -> Optional.ofNullable(callback.apply(v)))
                .orElse(null);
    }

 * either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.util;

import org.dbflute.optional.OptionalEntity;

/**
 * Utility class for Optional operations.
 */
public class OptionalUtil {

    /**
     * Default constructor.
     */
    private OptionalUtil() {
        // Default constructor
    }

    /**

 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.api;

import java.util.Optional;

import org.apache.maven.api.annotations.Experimental;
import org.apache.maven.api.annotations.Nonnull;
import org.apache.maven.api.model.PluginExecution;
import org.apache.maven.api.plugin.descriptor.MojoDescriptor;

     * class could be unloaded after the above call to `getEnumConstants` but before we call
     * `get()`, but that is vanishingly unlikely.
     */
    return ref == null ? Optional.absent() : Optional.fromNullable(enumClass.cast(ref.get()));
  }

  static String formatCompact4Digits(double value) {
    return String.format(Locale.ROOT, "%.4g", value);
  }

#### Possibly `None` (Optional)

Ви можете оголосити, що значення може мати тип, наприклад `str`, але також може бути `None`.

У Python 3.6 і вище (включаючи Python 3.10) ви можете оголосити його, імпортувавши та використовуючи `Optional` з модуля `typing`.

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

 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.api;

import java.util.List;
import java.util.Optional;
import java.util.function.Predicate;
import java.util.stream.Stream;

import org.apache.maven.api.annotations.Experimental;
import org.apache.maven.api.annotations.Immutable;

You can define arbitrarily deeply nested models:

{* ../../docs_src/body_nested_models/tutorial007_py310.py hl[7,12,18,21,25] *}

/// info

Notice how `Offer` has a list of `Item`s, which in turn have an optional list of `Image`s

///

## Bodies of pure lists { #bodies-of-pure-lists }