/// <summary>
/// Get alll the shows and then their respective casts. Filtered with existing shows already in the database.
/// </summary>
/// <returns>List<TVShow></returns>
private async Task <List <TVShow> > getShowsToInsert()
{
List <TVShow> showlist = await ApiHelpers.getAllShowsAsync();
var existingShows = _context.TVShow.ToDictionary(m => m.id, m => m);
var showDictionary = showlist.ToDictionary(m => m.id, m => m);
var showListToInsert = showDictionary.Where(d => !existingShows.ContainsKey(d.Key)).Select(m => m.Value).ToList();
return(await ApiHelpers.UpdateCastsAsync(showListToInsert));
}