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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 get_location(self, obj):
 """ return user's location """

        if not obj.city and not obj.country:
            return None
        elif obj.city and obj.country:
            return '%s, %s' % (obj.city, obj.country)
        elif obj.city or obj.country:
            return obj.city or obj.country