anchor.diff:    // Number of elements in the splay tree.
     int _count = 0;
   
  -  /// Counter incremented whenever the keys in the map changes.
  +  /// Counter incremented whenever the keys in the map change.
     ///
     /// Used to detect concurrent modifications.
     int _modificationCount = 0;
  
positive.code:   /// work on all `E` instances.
    ///
    /// For operations that add elements to the set, the user is supposed to not
    /// pass in objects that doesn't work with the compare function.
    ///
    /// The methods [contains], [remove], [lookup], [removeAll] or [retainAll]
    /// are typed to accept any object(s), and the [isValidKey] test can used to
  
negative.code:   ///
    /// The keys must all be instances of [K] and the values of [V].
    /// The [other] map itself can have any type.
    /// Example:
    /// ```dart
    /// final baseMap = <int, Object>{3: 'C', 1: 'A', 2: 'B'};
    /// final fromBaseMap = SplayTreeMap<int, String>.from(baseMap);
    /// print(fromBaseMap); // {1: A, 2: B, 3: C}
    /// ```
    factory SplayTreeMap.from(Map<dynamic, dynamic> other,
        [int Function(K key1, K key2)? compare,
        bool Function(dynamic potentialKey)? isValidKey]) {
  