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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 _id(self):
 r""" The `SSHKey`'s ``id`` field, or if that is not defined, its ``fingerprint`` field. If neither field is defined, accessing this attribute raises a `TypeError`. """

        if self.get("id") is not None:
            return self.id
        elif self.get("fingerprint") is not None:
            return self.fingerprint
        else:
            raise TypeError('SSHKey has neither .id nor .fingerprint')