It is currently only possible to do so using the Javascript API; however, you will not be able to do so using this property within the Spotfire dashboard via IronPython.
This report can be done using the Document.onDocumentReady method in Web Player JavaScript API : https://docs.tibco.com/pub/sfire_dev/area/doc/api/TIB_sfire_Web_Player_JavaScript_API_Reference/html/M_spotfire_webPlayer_Document_onDocumentReady.htm