public List <User> ZodiacFriends(IFriendsBy i_FriendsBy, List <User> i_allFriends) { List <User> friendsByZoaidc = new List <User>(); foreach (User friend in i_allFriends) { eZodiac friendsZodiacSigns = GetZodiac(DateTime.ParseExact(friend.Birthday, "MM/dd/yyyy", CultureInfo.InvariantCulture)); if (i_FriendsBy.FriendsBy(friendsZodiacSigns.ToString())) { friendsByZoaidc.Add(friend); } } return(friendsByZoaidc); }