[SAGA-RG] Semantics of 'existing' Attributes?

Hi all, What does the word 'existing' mean in the description of the Attributes interface in GFD.90? For example, the spec says that list_attributes() returns 'existing attribute keys'. Say we do: jd = new job_description() print jd.list_attributes() The C++ Python wrapper will print an empty list. The Java implementation will print all defined job description attributes. So, the C++ impl interprets 'existing' as 'having a value'. Since it does not set any default values (a bug?) it prints an empty list. The Java impl interprets 'existing' as 'being defined', and prints all defined attributes. What would be the correct behavior? regards, Mathijs