'Gets LUN on the Unity system.
:param lun_id: id of the LUN
:param name: name of the LUN
:return: `UnityLun` object'

def get_lun(self, lun_id=None, name=None):

    lun = None
    if ((lun_id is None) and (name is None)):
        LOG.warning('Both    lun_id    and    name    are    None    to    get    LUN.    Return    None.')
    else:
        try:
            lun = self.system.get_lun(_id=lun_id, name=name)
        except storops_ex.UnityResourceNotFoundError:
            LOG.warning("LUN    id=%(id)s,    name=%(name)s    doesn't    exist.", {'id': lun_id, 'name': name})
    return lun
