+ # ensure site record exists
+ site = slices.verify_site(hrn, slice_record, peer, sfa_peer)
+ # ensure slice record exists
+ slice = slices.verify_slice(hrn, slice_record, peer, sfa_peer)
+ # ensure person records exists
+ persons = slices.verify_persons(hrn, slice, users, peer, sfa_peer)
+ # ensure slice attributes exists
+ slices.verify_slice_attributes(slice, requested_attributes)
+