In the python code of the models we can use orm.except_orm to display an error popup.

If I try to use it in a report parser (e.g. a class inheriting report_sxw.parse_rml) it won't work: instead of my error I'll get

SyntaxError: JSON.parse: unexpected end of data at line 2 column 1 of the JSON data

And my custom error will be visible only in my log.

How can I display an error popup from a report parser class?