Provide an example implementation of your BAdI for your customers. Note that only one example implementation is allowed. The example code must be written in restricted ABAP because this is the template for the key users, and the key users are only allowed to write restricted ABAP code.
As you can only use the ABAP language version ABAP for Cloud Development in your example class, it could happen that you write code that isn't allowed to be used by key users. To prevent this from happening, please create an implementation of your BAdI in the Custom Logic app on your test system. If you don't see syntax errors on the UI, your example code is written in restricted ABAP. Have a look at the code reference for key users here: Statements in ABAP for Key Users.