schema:     ROUTE-SET-SCHEMA
ref:        dn42.route-set
key:        route-set    required  single    primary schema
key:        descr        optional  single
key:        mnt-by       required  multiple  lookup=dn42.mntner
key:        members      optional  deprecate multiple  lookup=dn42.route-set
key:        mp-members   optional  multiple  lookup=dn42.route 
key:        mbrs-by-ref  optional  multiple  lookup=dn42.route
key:        admin-c      optional  multiple  lookup=dn42.person,dn42.role
key:        tech-c       optional  multiple  lookup=dn42.person,dn42.role
key:        remarks      optional  multiple
mnt-by:     XUU-MNT
mnt-by:     HEXA-MNT