'Gets the list of LUNs on filer.'

def get_lun_list(self):

    lun_list = []
    if self.volume_list:
        for vol in self.volume_list:
            try:
                luns = self._get_vol_luns(vol)
                if luns:
                    lun_list.extend(luns)
            except netapp_api.NaApiError:
                LOG.warning('Error    finding    LUNs    for    volume    %s.    Verify    volume    exists.', vol)
    else:
        luns = self._get_vol_luns(None)
        lun_list.extend(luns)
    return lun_list
