What is the tennis ball in front of?
The tennis ball is in front of the racket.
    src        edge_attr  dst
0     5  to the right of    9
1     5      in front of   11
2     6          wearing    0
3     6          holding   11
4     6          wearing    4
5     8   to the left of   10
6     9   to the left of    5
7     9   to the left of   11
8     9   to the left of   12
9    10  to the right of    8
10   11           behind    5
11   11  to the right of    9
12   12  to the right of    9