code: def request(self, apdu):
          
          if _debug: ClientSSM._debug("request %r", apdu)
  
          # make sure it has a good source and destination
          apdu.pduSource = None
          apdu.pduDestination = self.pdu_address
  
          # send it via the device
          self.ssmSAP.request(apdu)
docs: This function is called by client transaction functions when it wants
          to send a message to the device.