(OC.merge_maybes (database cfg) (OC.database opt_cfg))
(merge (detail cfg) (OC.detail opt_cfg))
(OC.merge_maybes (host cfg) (OC.host opt_cfg))
(OC.merge_maybes (database cfg) (OC.database opt_cfg))
(merge (detail cfg) (OC.detail opt_cfg))
(OC.merge_maybes (host cfg) (OC.host opt_cfg))