code: def saveDevices(self, remote):
          
          LOG.debug("RPCFunctions.saveDevices: devicefile: %s, _devices_raw: %s" % (
              self.devicefile, str(self._devices_raw[remote])))
          if self.devicefile:
              try:
                  with open(self.devicefile, 'w') as df:
                      df.write(json.dumps(self._devices_raw[remote]))
                  return True
              except Exception as err:
                  LOG.warning(
                      "RPCFunctions.saveDevices: Exception saving _devices_raw: %s", str(err))
                  return False
          else:
              return True
docs: We save known devices into a json-file so we don't have to work through the whole list of devices the CCU / Homegear presents us