+To create a payment for 3 invoices that were all paid together, all with skonto:
+ my $ar1 = SL::DB::Manager::Invoice->find_by(invnumber=>'20');
+ my $ar2 = SL::DB::Manager::Invoice->find_by(invnumber=>'21');
+ my $ar3 = SL::DB::Manager::Invoice->find_by(invnumber=>'22');
+ $ar1->create_bank_transaction(amount => ($ar1->amount_less_skonto + $ar2->amount_less_skonto + $ar2->amount_less_skonto),
+ purpose => 'Rechnungen 20, 21, 22',
+ );
+