async def METHOD_NAME(self, data=b"Test bytes", large=False):
    _, ciphertext, keys = await self._get_data_cypher_keys(data)
    plaintext = decrypt_attachment(
        ciphertext,
        keys["key"]["k"],
        keys["hashes"]["sha256"],
        keys["iv"],
    )
    assert plaintext == b"Test bytes" * (16384 if large else 1)