@MaleeshaW $ANY implies the class can be dynamic as and when in runtime you pic, but even if u don't explicitly say that it will behave in that way only, as a best practice don't use hardcoded pyworkpages in application as pyworkpage context can change with different parent or child classes and activity or dt reuse can be hinder or context issues may arise.

added one such example attachment where pega uses $class is when they use pxresults page list property we then explicitly define them in pages and classes to override that.

Hope this helps in better understanding.