Return iterable of entries, where each entry is the key:set pair.
For example, if the map is {1: {a, b}, 2: {x, y}}, it will return [(1:{a,b}), 2:{x, y}].
{1: {a, b}, 2: {x, y}}
[(1:{a,b}), 2:{x, y}]
Iterable<MapEntry<K, ISet<V>>> get entries => _mapOfSets.entries;