invoices method

@override Future<List<DVInvoice>> invoices(Object customer, { int limit = 20, })

None: nothing here charges anybody, so there is nothing to invoice.

Empty rather than an error, because a local billing setup is a working configuration and a billing history page against it should render an empty history rather than fail.

Implementation

@override
Future<List<DVInvoice>> invoices(Object customer, {int limit = 20}) async =>
    const <DVInvoice>[];