docs: def _set_sysfs(self, fcp, target_wwpn, target_lun):
          """rhel6 set WWPN and LUN in sysfs"""
          device = '0.0.%s' % fcp
          port_add = "echo '%s' > " % target_wwpn
          port_add += "/sys/bus/ccw/drivers/zfcp/%s/port_add" % device
          unit_add = "echo '%s' > " % target_lun
          unit_add += "/sys/bus/ccw/drivers/zfcp/%(device)s/%(wwpn)s/unit_add\n"\
                      % {'device': device, 'wwpn': target_wwpn}
          return '\n'.join((port_add,
                            unit_add))