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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 leveled(self):
 """Return all countries with a level set"""

        
        # Compatibility support for Django<1.6
        safe_get_queryset = (self.get_query_set if hasattr(self, 'get_query_set') else self.get_queryset)
        
        return safe_get_queryset.exclude(level=0)