public static void AddValue <TKey, TValue> ( this IDictionary <TKey, IList <TValue> > dictionary, [DisallowNull] TKey key, TValue value ) => dictionary.GetValueOrAddNew(key, () => new List <TValue>()).Add(value);
public static void AddValue <TKey, TValue> ( this IDictionary <TKey, IList <TValue> > dictionary, [DisallowNull] TKey key, TValue value ) => dictionary.GetValueOrAddNew(key, () => new List <TValue>()).Add(value);