Finds old references to stashed fields and deletes them

def purgeDeletedWidgets():
        """Finds old references to stashed fields and deletes them"""
        toremove = []
        for field in AbstractEditorWidget.funit_fields:
            if sip.isdeleted(field):
                toremove.append(field)
        for field in toremove:
            AbstractEditorWidget.funit_fields.remove(field)

        toremove = []
        for field in AbstractEditorWidget.tunit_fields:
            if sip.isdeleted(field):
                toremove.append(field)
        for field in toremove:
            AbstractEditorWidget.tunit_fields.remove(field)