'Attaches a `UnityLun` or `UnitySnap` to a `UnityHost`.
:param host: `UnityHost` object
:param lun_or_snap: `UnityLun` or `UnitySnap` object
:return: hlu'

@staticmethod
def attach(host, lun_or_snap):

    try:
        return host.attach(lun_or_snap, skip_hlu_0=True)
    except storops_ex.UnityResourceAlreadyAttachedError:
        return host.get_hlu(lun_or_snap)
