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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_one(self):
 """get one row from the db"""

        self.default_val = None
        o = self.default_val
        d = self._query('get_one')
        if d:
            o = self.orm_class(d, hydrate=True)
        return o