docs: 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()