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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 derivation(self):
 """ Deserialize and return a Derivation object for UDF- or JSON-formatted derivation data; otherwise return the original string. """

        drv = self.get('derivation')
        if drv is not None:
            if isinstance(drv, dict):
                drv = Derivation.from_dict(drv)
            elif isinstance(drv, stringtypes):
                drv = Derivation.from_string(drv)
        return drv