Viewpoint Extract Expression Builder: Extract Elements with Defined Value (ignore inherited values)

Summary: Defining a Viewpoint Extract for Non-Inherited Properties.

I am using a property in a viewpoint that has inheritance enabled. I would like to define an extract that exclusively returns elements with an explicitly defined mapping for this property. Elements that carry values through inheritance should be ignored. Therefore, I am looking for a way to check for ‘ NOT.inheritedValue’ or ‘ .isExplicit’. I also tried an expression like: return 'node.properties.CustomABC.isNull.not', but it retrieved an incomplete result!

Many Thanks in advance.

Best Regards Andreas.