For the elements contained in the source sequence, returns the concatenated
sequences of descendant nodes of such elements, including the elements
themselves, in document order.
Returns
The concatenated, flat sequence of descendant nodes, including
the source elements, in document order
For the elements contained in the source sequence, returns the concatenated sequences of descendant nodes of such elements, including the elements themselves, in document order.
Returns
The concatenated, flat sequence of descendant nodes, including the source elements, in document order