Is it possible to pass list or dict in on_change function from xml?

I ofcourse tried to pass a dict as follows with no luck: .py file: def onchange_continent(self, cr, uid, id, testDict, continent_id=None, context=None): print testDict but this throws an error: Error: Could not get field with name '{'item1':1' for onchange 'onchange_continent({'item1':1, 'item2':2}, continent_id)' where is the code for parsing the on_change function, maybe I can edit that for our module? Thank You.