def _safe_find_iso_sr(session):
    sr_ref = _find_iso_sr(session)
    if sr_ref is None:
        raise exception.NotFound(_('Cannot find SR of content-type ISO'))
    return sr_ref
Logout a user and display a logout message.
dataset/ETHPy150Open BU-NU-CLOUD-SP16/Trusted-Platform-Module-nova/nova/virt/xenapi/vm_utils.py/_safe_find_iso_sr--crossover with--dataset/ETHPy150Open openstack/horizon/horizon/middleware.py/HorizonMiddleware._logout