private bool FilterCustomers(Customer entity)
 {
     return (entity.FoundryID == this.ID);
 }
 private void AttachCustomers(Customer entity)
 {
     entity.Foundry = this;
 }
 private void DetachCustomers(Customer entity)
 {
     entity.Foundry = null;
 }
 private bool FilterCustomer(Customer entity)
 {
     return (entity.ID == this.CustomerID);
 }