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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 compute_message_authenticator(radius_packet, packed_req_authenticator, shared_secret):
 """ Computes the "Message-Authenticator" of a given RADIUS packet. """


        data = prepare_packed_data(radius_packet, packed_req_authenticator)
        radius_hmac = hmac.new(shared_secret, data, hashlib.md5)

        return radius_hmac.digest()