The interface provides {HEAD ~ access} to the data elements and {TAIL ~ the order keys} in the dataset in a type safe manner 
to
The interface provides { HEAD ~ access } to the data elements and { TAIL ~ the order keys } in the dataset in a type safe manner
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH