public async Task AddShows(ICollection <Show> shows)
{
if (shows == null || !shows.Any())
{
return;
}
await AddAbsentShows(shows);
await AddAbsentPeople(shows.SelectMany(s => s.People.Select(p => p.Person)).ToList());
await AddAbsentAssocs(shows.SelectMany(s => s.People).ToList());
await _myDbContext.Save();
}