def _iteritems(self):
        seen = set()
        for dict_ in self.dicts:
            for item in six.iteritems(dict_):
                k = item[0]
                if k in seen:
                    continue
                seen.add(k)
                yield item
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.5/django/utils/datastructures.py/MergeDict._iteritems/original