public Task <XtrfResult <Data.Provider> > GetSingle(long providerId, GetSingleParameter param = null)
=> Get <Data.Provider>(new ExecuteParams($"/providers/{providerId}", param));
public Task <XtrfResult <CustomerInvoice> > GetSingle(long invoiceId, GetSingleParameter param = null)
=> Get <CustomerInvoice>(new ExecuteParams($"/accounting/customers/invoices/{invoiceId}", param));
