public Task <Option <CollectionList, Error> > ExecuteAsync(ListArguments arguments) =>
arguments
.SomeNotNull <ListArguments, Error>("You must provide non-null arguments.")
.Filter(args => !string.IsNullOrEmpty(args.Path), "You must provide a non-empty path.")
.Filter(args => args.PageSize > 0, "The page size must be larger than 0.")
.FlatMapAsync(args =>
_musicCollection
.GetEntriesAsync(args.PageSize, args.Path)
.MapAsync(async tracks => new CollectionList
{
Entries = tracks
}));
