fun getGroupByNBar(y1: List<Any>, y2: List<Any>): Map<List<Any>, NodeTransfer> (source)
Retrieve from the database all pairs (x,n) s.t. x ∈ X ∧ n.k_min < (x, y1) < (x, y2) < n.k_max, having maximum level.
This method can only be invoked when the key type is composite, i.e. admits a group and a least significant part.
y1 - the list that identify the minimum element in the range.
y2 - the list that identify the maximum element in the range.
Return
the retrieved pair (x,n).