_products.Distinct((x, y) => x.Id == y.Id, x.Id.GetHashCode());
_products.Distinct((x, y) => x.Price == y.Price, x.Price.GetHashCode());
_persons.Distinct((x, y) => x.LastName == y.LastName, x.LastName.GetHashCode());
_persons.Distinct((x, y) => x.FirstName == y.FirstName, x.FirstName.GetHashCode());
_persons.Distinct((x, y) => x.Address.City == y.Address.City, x.Address.City.GetHashCode());