loader

type BulkLoader interface {
	LoadMonthInvoices(yearMonth model.YearMonth) (invoices []model.Invoice, err error)
	LoadMonthInvoicesByPaymentType(yearMonth model.YearMonth) (invoices map[payment_type.PaymentType][]model.Invoice, err error)
	LoadProducts() (products map[string]model.Product, err error)
	LoadCustomers() (customers map[int]model.Customer, err error)
	LoadCustomersAndProducts() (customers map[int]model.Customer, products map[string]model.Product, err error)
	LoadMonthInvoicesCustomersAndProducts(yearMonth model.YearMonth) (invoices []model.Invoice, customers map[int]model.Customer, products map[string]model.Product, err error)
}