protected override IEnumerator <KeyValuePair <keyˈ, valueˈ> > GetEnumerator() => InnerDictionary.AsEnumerable().MapValues(Projection).GetEnumerator();
protected override IEnumerator <KeyValuePair <keyˈ, valueˈ> > GetEnumerator() => InnerDictionary.AsEnumerable().MapValues(Projection).GetEnumerator();