[rules-users] Migration 3 to 4 (replace "->")

In Drools 3 i used the following code (in a DSL file): [when]ist BlaBlub=BlaBlub(number : id -> ( BlaClass.staticFunction( number )) where id can be resolved be method getId in class BlaBlub and staticFunction ist a public static function in a helper class. Drools 4 doesn't allow me this construct, how should this be migrated? Any help is much appreciated Cheers Markus