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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def complex_filter(self, filter_obj):
 """ Returns a new QuerySet instance with filter_obj added to the filters. filter_obj can be a Q object (or anything with an add_to_query() method) or a dictionary of keyword lookup arguments. This exists to support framework features such as 'limit_choices_to', and usually it will be more natural to use other methods. """

        if isinstance(filter_obj, Filter):
            clone = self._clone()
            clone._filters.add(filter_obj)
            return clone
        return self._filter_or_exclude(None, **filter_obj)