anchor.diff:    /// Set<SuperType> superSet = ...;
     /// Iterable<SuperType> tmp = superSet.where((e) => e is SubType);
     /// Set<SubType> subSet = LinkedHashSet<SubType>.from(tmp);
  +  /// ```
  +  /// Example:
  +  /// ```dart
  +  /// final numbers = <num>[10, 20, 30];
  +  /// final setFrom = LinkedHashSet<int>.from(numbers);
  +  /// print(setFrom); // {10, 20, 30}
     /// ```
     factory LinkedHashSet.from(Iterable<dynamic> elements) {
       LinkedHashSet<E> result = LinkedHashSet<E>();
  
positive.code: /// An element that was added after another will occur later in the iteration.
  /// Adding an element that is already in the set
  /// does not change its position in the iteration order,
  /// but removing an element and adding it again,
  /// will make it the last element of an iteration.
  ///
  /// Most simple operations on `HashSet` are done in (potentially amortized)
  /// constant time: [add], [contains], [remove], and [length], provided the hash
  /// codes of objects are well distributed..
  abstract class LinkedHashSet<E> implements Set<E> {
    /// Create an insertion-ordered hash set using the provided
    /// [equals] and [hashCode].
  
negative.code:   /// [hashCode] must be consistent with [equals].
    ///
    /// If you supply one of [equals] and [hashCode],
    /// you should generally also supply the other.
    ///
    /// Some [equals] or [hashCode] functions might not work for all objects.
    /// If [isValidKey] is supplied, it's used to check a potential element
  