docs: def VerifyCoARequest(self):
          """Verify request authenticator.
          :return: True if verification failed else False
          :rtype: boolean
          """
          assert(self.raw_packet)
          hash = md5_constructor(self.raw_packet[0:4] + 16 * six.b('\x00') +
                  self.raw_packet[20:] + self.secret).digest()
          return hash == self.authenticator