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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 from_key_bytes(cls, algorithm, key_bytes):
 """Builds a `Signer` from an algorithm suite and a raw signing key. :param algorithm: Algorithm on which to base signer :type algorithm: aws_encryption_sdk.identifiers.Algorithm :param bytes key_bytes: Raw signing key :rtype: aws_encryption_sdk.internal.crypto.Signer """

        key = serialization.load_der_private_key(data=key_bytes, password=None, backend=default_backend())
        return cls(algorithm, key)