anchor.diff:    /// The keys of `map` are the `list` values converted to strings,
     /// and the values of the `map` are the squares of the `list` values:
     /// ```dart
  -  /// List<int> list = [1, 2, 3];
  -  /// var map = Map<String, int>.fromIterable(list,
  +  /// final numbers = <int>[1, 2, 3];
  +  /// final map = Map<String, int>.fromIterable(numbers,
     ///     key: (item) => item.toString(),
     ///     value: (item) => item * item);
  -  /// // map is {"1": 1, "2": 4, "3": 9}
  +  /// print(map); // {1: 1, 2: 4, 3: 9}
     /// ```
     /// If no values are specified for [key] and [value],
     /// the default is the identity function.
  
positive.code:   ///
    /// Returns true if any of the values in the map are equal to `value`
    /// according to the `==` operator.
    bool containsValue(Object? value);
  
    /// Whether this map contains the given [key].
    ///
    /// Returns true if any of the keys in the map are equal to `key`
    /// according to the equality used by the map.
    bool containsKey(Object? key);
  
    /// The value for the given [key], or `null` if [key] is not in the map.
  
negative.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
    /// final rings = <bool>[false, false, true, true];
    /// final planets = <String>{'Earth', 'Mars', 'Jupiter', 'Saturn'};
    /// final map = Map<String, bool>.fromIterables(planets, rings);
    /// print(map); // {Earth: false, Mars: false, Jupiter: true, Saturn: true}
    /// ```
    /// If [keys] contains the same object multiple times,
    /// the value of the last occurrence overwrites any previous value.
  