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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 _decrypt(ascii_armor_message: str, signing_key: SigningKey) -> str: """ Decrypt a message from ascii armor format :param ascii_armor_message: Utf-8 message :param signing_key: SigningKey instance created from credentials :return: """

        data = signing_key.decrypt_seal(base64.b64decode(ascii_armor_message))

        return data.decode('utf-8')