+sub create_zugferd_invoices_for_this_customer {
+ my ($self) = @_;
+
+ no warnings 'once';
+ return $::instance_conf->get_create_zugferd_invoices if $self->create_zugferd_invoices == -1;
+ return $self->create_zugferd_invoices;
+}
+
+sub default_billing_address {
+ my $self = shift;
+
+ die 'not an accessor' if @_ > 1;
+ return first { $_->default_address } @{ $self->additional_billing_addresses };
+}
+