"Get Started with ABAP Programming on SAP BTP": course part: "Defining a local class"

[gerald_kluge]

Hi,
i have a problem with the samples of this course part.
Declarations like:
       DATA carrier_id TYPE /dmo/carrier_id.
   DATA connection_id TYPE /dmo/connection_id.

are not resolved.
Possibly my package ZS4D400_xx is not nested in the right order?

Thanks for any hint.
Gerald