}
  }

  /**
   * Returns a builder that creates immutable sorted maps whose keys are ordered by their natural
   * ordering. The sorted maps use {@link Ordering#natural()} as the comparator.
   */
  public static <K extends Comparable<?>, V> Builder<K, V> naturalOrder() {
    return new Builder<>(Ordering.natural());
  }

  /**
   * Returns a builder that creates immutable sorted maps with an explicit comparator. If the

   */
  public double populationCovariance() {
    checkState(count() != 0);
    return sumOfProductsOfDeltas / count();
  }

  /**
   * Returns the sample covariance of the values. The count must be greater than one.
   *
   * <p>This is not guaranteed to return zero when the dataset consists of the same pair of values
   * multiple times, due to numerical errors.
   *
   * <h3>Non-finite values</h3>
   *

    }

    /**
     * Creates and returns a new instance of {@link ArrayDeque}.
     *
     * @param <E> the element type of {@link ArrayDeque}
     * @return a new instance of {@link ArrayDeque}
     * @see ArrayDeque#ArrayDeque()
     */
    public static <E> ArrayDeque<E> newArrayDeque() {
        return new ArrayDeque<>();
    }

    /**
     * Creates and returns a new instance of {@link ArrayDeque}.

   * minimum hashtable size, whichever is greater.
   */
  static int tableSize(int expectedSize) {
    // We use entries next == 0 to indicate UNSET, so actual capacity is 1 less than requested.
    return max(MIN_HASH_TABLE_SIZE, closedTableSize(expectedSize + 1, 1.0));
  }

  /** Creates and returns a properly-sized array with the given number of buckets. */

  // TODO(user): cache all field accesses in local vars

  /** Creates an empty {@code CompactHashSet} instance. */
  public static <E extends @Nullable Object> CompactHashSet<E> create() {
    return new CompactHashSet<>();
  }

  /**
   * Creates a <i>mutable</i> {@code CompactHashSet} instance containing the elements of the given
   * collection in unspecified order.
   *

    private TestUtils() {
        // Utility class
    }

    /**
     * Creates a mock UpgradeContext with default settings.
     *
     * @return a mock UpgradeContext
     */
    public static UpgradeContext createMockContext() {
        return createMockContext(Paths.get("/project"));
    }

    /**
     * Creates a mock UpgradeContext with the specified working directory.
     *

    }
  }

  /**
   * Returns a builder that creates immutable sorted maps whose keys are ordered by their natural
   * ordering. The sorted maps use {@link Ordering#natural()} as the comparator.
   */
  public static <K extends Comparable<?>, V> Builder<K, V> naturalOrder() {
    return new Builder<>(Ordering.natural());
  }

  /**
   * Returns a builder that creates immutable sorted maps with an explicit comparator. If the

     * now-deprecated {@link #transitiveClosure(Graph)} method.
     */
    ADD_SELF_LOOPS_ALWAYS,
    /**
     * Add a self-loop to each node that is incident to a cycle of length one or greater in the
     * original graph.
     */
    ADD_SELF_LOOPS_FOR_CYCLES
  }

  /**
   * Returns the set of nodes that are reachable from {@code node}. Specifically, it returns all

    private static final long serialVersionUID = -2154525994315946504L;

    /**
     * Creates a {@link ClIllegalStateException}.
     */
    public ClIllegalStateException() {
        super();
    }

    /**
     * Creates a {@link ClIllegalStateException}.
     *
     * @param message
     *            Message
     */

 * <ul>
 *   <li>{@link #suggest()}: Creates a new SuggestRequestBuilder for querying suggestions.</li>
 *   <li>{@link #popularWords()}: Creates a new PopularWordsRequestBuilder for querying popular words.</li>
 *   <li>{@link #refresh()}: Refreshes the suggestion indices.</li>
 *   <li>{@link #shutdown()}: Shuts down the thread pool.</li>
 *   <li>{@link #createIndexIfNothing()}: Creates a new index if no index exists.</li>