1 [ Tree (Cell 1:1 3:10 (NodeHeader (HeaderSection 2)))
2 [ Tree (Cell 1:4 1:8 NodePara)
3 [ Tree (Cell 1:4 1:8 (NodeToken (TokenText "sec1"))) []
5 , Tree (Cell 2:3 2:10 (NodeHeader (HeaderSection 1)))
6 [ Tree (Cell 2:5 2:10 NodePara)
7 [ Tree (Cell 2:5 2:10 (NodeToken (TokenText "sub11"))) []
10 , Tree (Cell 3:3 3:10 (NodeHeader (HeaderSection 1)))
11 [ Tree (Cell 3:5 3:10 NodePara)
12 [ Tree (Cell 3:5 3:10 (NodeToken (TokenText "sub12"))) []