anchor.diff:    /// and adds the key with the returned value to the map.
     ///
     /// If the key is not present, [ifAbsent] must be provided.
  +  /// ```dart
  +  /// final planetsFromSun = <int, String>{1: 'Mercury', 2: 'unknown',
  +  ///   3: 'Earth'};
  +  /// // Update value for known key value 2.
  +  /// planetsFromSun.update(2, (value) => 'Venus');
  +  /// print(planetsFromSun); // {1: Mercury, 2: Venus, 3: Earth}
  +  ///
  +  /// final largestPlanets = <int, String>{1: 'Jupiter', 2: 'Saturn',
  +  ///   3: 'Neptune'};
  +  /// // Key value 8 is missing from list, add it using [ifAbsent].
  +  /// largestPlanets.update(8, (value) => 'New', ifAbsent: () => 'Mercury');
  +  /// print(largestPlanets); // {1: Jupiter, 2: Saturn, 3: Neptune, 8: Mercury}
  +  /// ```
     V update(K key, V update(V value), {V ifAbsent()?});
   
     /// Updates all values.
     ///
     /// Iterates over all entries in the map and updates them with the result
     /// of invoking [update].
  +  /// ```dart
  +  /// final terrestrial = <int, String>{1: 'Mercury', 2: 'Venus', 3: 'Earth'};
  +  /// terrestrial.updateAll((key, value) => value.toUpperCase());
  +  /// print(terrestrial); // {1: MERCURY, 2: VENUS, 3: EARTH}
  +  /// ```
     void updateAll(V update(K key, V value));
   
     /// Removes all entries of this map that satisfy the given [test].
  +  /// ```dart
  +  /// final terrestrial = <int, String>{1: 'Mercury', 2: 'Venus', 3: 'Earth'};
  +  /// terrestrial.removeWhere((key, value) => value.startsWith('E'));
  +  /// print(terrestrial); // {1: Mercury, 2: Venus}
  +  /// ```
     void removeWhere(bool test(K key, V value));
   
     /// Look up the value of [key], or add a new entry if it isn't there.
  
positive.code:   /// The map construction iterates over [keys] and [values] simultaneously,
    /// and adds an entry to the map for each pair of key and value.
    /// ```dart
    /// List<String> letters = ['b', 'c'];
    /// List<String> words = ['bad', 'cat'];
    /// var map = Map.fromIterables(letters, words);
    /// // map is {"b": "bad", "c": "cat"}
    /// ```
    /// If [keys] contains the same object multiple times,
    /// the value of the last occurrence overwrites any previous value.
  
negative.code:   /// Equivalent to the map literal:
    /// ```dart
    /// <K, V>{for (var e in entries) e.key: e.value}
    /// ```
    /// Example:
    /// ```dart
    /// final moonCount = <String, int>{'Mercury': 0, 'Venus': 0, 'Earth': 1,
    ///   'Mars': 2, 'Jupiter': 79, 'Saturn': 82, 'Uranus': 27, 'Neptune': 14};
    /// final map = Map.fromEntries(moonCount.entries);
    /// ```
    factory Map.fromEntries(Iterable<MapEntry<K, V>> entries) =>
        <K, V>{}..addEntries(entries);
  