public ProductsController(IServicesProducts<Products> serviceProducts, IServicesVendors<Vendors> serviceVendors)
 {
     this.serviceProducts = serviceProducts;
     this.serviceVendors = serviceVendors;
 }
 public PurchaseController(IServicesPurchases<Purchase> servicePurchase, IServicesProducts<Products> serviceProducts, IServicesBuyers<Buyers> serviceBuyers)
 {
     this.servicePurchase = servicePurchase;
     this.serviceProducts = serviceProducts;
     this.serviceBuyers = serviceBuyers;
 }