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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 key_bytes(self):
 """Returns the raw signing key. :rtype: bytes """

        return self.key.private_bytes(
            encoding=serialization.Encoding.DER,
            format=serialization.PrivateFormat.PKCS8,
            encryption_algorithm=serialization.NoEncryption(),
        )