*
     * @return the root node of the dependency graph or {@code null} if none
     */
    @Nullable
    Node getRoot();

    /**
     * The ordered list of the flattened dependency nodes.
     *
     * @return the ordered list of the flattened dependency nodes
     */
    @Nonnull
    List<Node> getNodes();

    /**

		e := d.Cache[id]
		if len(e.Children) > 0 {
			e = d.flatten(e)
		}
		m[id] = e
	}
	return m
}

// flatten all children of the root into the root element and return it.
func (d *dataUsageCache) flatten(root dataUsageEntry) dataUsageEntry {
	for id := range root.Children {
		e := d.Cache[id]
		if len(e.Children) > 0 {
			e = d.flatten(e)
		}
		root.merge(e)
	}
	root.Children = nil

 * If the type is {@link org.apache.maven.api.Node Node} or
 * {@code List<}{@link org.apache.maven.api.Node Node}{@code >},
 * and {@code pathScope != ""}, the dependencies will be <i>flattened</i>.
 * Else the dependencies will be <i>resolved</i> and {@code pathScope} must be non empty,
 * and the field type can be {@link org.apache.maven.api.Node Node},
 * {@code List<}{@link org.apache.maven.api.Node Node}{@code >},

                session, DependencyResolverRequest.RequestType.FLATTEN, project, scope));
    }

    @Nonnull
    default DependencyResolverResult flatten(@Nonnull DependencyResolverRequest request) {
        if (request.getRequestType() != DependencyResolverRequest.RequestType.FLATTEN) {
            throw new IllegalArgumentException("requestType should be FLATTEN when calling flatten()");
        }
        return resolve(request);
    }

	CompName1 string `gorm:"index:,unique,composite:idx_compname_1,option:NULLS NOT DISTINCT;not null"`
	CompName2 string `gorm:"index:,composite:idx_compname_1"`

	// Composite Index: Flattened structure.
	Data0A string `gorm:"index:,composite:comp_id0"`
	Data0B string `gorm:"index:,composite:comp_id0"`

	// Composite Index: Nested structure.
	Data1A string `gorm:"index:,composite:comp_id1"`
	CompIdxLevel1C

            identifiers.put(ident, method);
          }
        }
      }
    }
    return ImmutableList.copyOf(identifiers.values());
  }

  /** Global cache of classes to their flattened hierarchy of supertypes. */
  private static final LoadingCache<Class<?>, ImmutableSet<Class<?>>> flattenHierarchyCache =
      CacheBuilder.newBuilder()
          .weakKeys()
          .build(

    /**
     * Shortcut for {@code getService(DependencyResolver.class).flatten(...)}.
     *
     * @param node node for which to get a flattened list
     * @param scope build path scope (main compile, test compile, etc.) of desired nodes
     * @return flattened list of node with the given build path scope

 * map from keys to <i>nonempty</i> collections of values:
 *
 * <ul>
 *   <li>a → 1, 2
 *   <li>b → 3
 * </ul>
 *
 * ... or as a single "flattened" collection of key-value pairs:
 *
 * <ul>
 *   <li>a → 1
 *   <li>a → 2
 *   <li>b → 3
 * </ul>
 *
 * <p><b>Important:</b> although the first interpretation resembles how most multimaps are

		path       string
		isNil      bool
		size, objs int
		flatten    bool
		oSizes     sizeHistogram
	}{
		{
			path:    "/",
			size:    363515,
			flatten: true,
			objs:    14,
			oSizes:  sizeHistogram{0: 7, 1: 5, 2: 2},
		},
		{
			path:    "/dir1",
			size:    342210,
			objs:    7,
			flatten: false,
			oSizes:  sizeHistogram{0: 2, 1: 3, 2: 2},
		},
		{

) {
  val commonName: Any?
    get() {
      return tbsCertificate.subject
        .flatten()
        .firstOrNull { it.type == ObjectIdentifiers.COMMON_NAME }
        ?.value
    }

  val organizationalUnitName: Any?
    get() {
      return tbsCertificate.subject
        .flatten()
        .firstOrNull { it.type == ObjectIdentifiers.ORGANIZATIONAL_UNIT_NAME }
        ?.value
    }