set:leading() returns the nodes in one node-set that come before the first node in the other node-set.
The node set to find nodes in that precede the first node in the second node set.
The node set to compare against.
A node-set containing the nodes from
nodeSet1 whose values precede the first node in
Note: If the first node in
nodeSet2 isn't contained in
nodeSet1, an empty set is returned. If
nodeSet2 is empty, then the result is