code: def setXpanId(self, xPanId):
          
          xpanid = ''
          print '%s call setXpanId' % self.port
          print xPanId
          try:
              if not isinstance(xPanId, str):
                  xpanid = self.__convertLongToString(xPanId)
  
                  # prepend '0' at the beginning
                  if len(xpanid) < 16:
                      xpanid = xpanid.zfill(16)
                      print xpanid
                      cmd = WPANCTL_CMD + 'setprop Network:XPANID %s' % xpanid
                      datasetCmd = WPANCTL_CMD + 'setprop Dataset:ExtendedPanId %s' % xpanid
              else:
                  xpanid = xPanId
                  cmd = WPANCTL_CMD + 'setprop Network:XPANID %s' % xpanid
                  datasetCmd = WPANCTL_CMD + 'setprop Dataset:ExtendedPanId %s' % xpanid
  
              self.xpanId = xpanid
              self.hasActiveDatasetToCommit = True
              return self.__sendCommand(cmd)[0] != 'Fail' and self.__sendCommand(datasetCmd)[0] != 'Fail'
          except Exception, e:
              ModuleHelper.WriteIntoDebugLogger('setXpanId() Error: ' + str(e))
docs: set extended PAN ID of Thread Network
  
          Args:
              xPanId: extended PAN ID in hex format
  
          Returns:
              True: successful to set the extended PAN ID
              False: fail to set the extended PAN ID