Who is on top of the wall?
The child is on top of the wall.
   src        edge_attr  dst
0    0               on    1
1    0        on top of    7
2    0        riding on    1
3    0          wearing   11
4    1            below    6
5    4               in    3
6    5   to the left of   10
7    7  to the right of    9
8    9   to the left of    7
9   10  to the right of    5