public bool WriteAll(IEnumerable <Person> people)
        {
            StringBuilder sb = new StringBuilder();

            foreach (var item in people)
            {
                item.Id        = -1;
                item.FavColour = UtilColor.Colors.FirstOrDefault(f => f.Id == item.FavColourId); //just to keep things in sync with Entity, Dumb hack
                sb.Append(UtilPerson.FromPerson(item));
            }
            File.AppendAllText(CSVFilePath, sb.ToString());
            _cachePeople.Clear();
            return(true);
        }