Never Store Calculation Result In Python Property
Always use properties to store document 'original' content (ie. the one which was
entered by the user). If you need to process document original content and store
the result somewhere, either make this is a new document (and Simulation should be
used if possible to track relations between calculated documents and original
documents), or this is a workflow variable (with complete historisation), or
this is an internal property to be handled within the class code.