What color is the vehicle in front of the tree?
The train is green.
    src        edge_attr  dst
0     2  to the right of    3
1     3   to the left of    2
2     4  to the right of    7
3     6   to the left of    7
4     7           behind   12
5     7  to the right of    6
6     7   to the left of   10
7     7  to the right of    9
8     7   to the left of   11
9     7   to the left of    4
10    9           behind   12
11    9   to the left of    7
12    9   to the left of   14
13   10  to the right of   14
14   10  to the right of   13
15   10  to the right of    7
16   10           behind   12
17   11  to the right of    7
18   11  to the right of   12
19   12      in front of   10
20   12      in front of    9
21   12   to the left of   11
22   12      in front of    7
23   13   to the left of   10
24   14  to the right of    9
25   14   to the left of   10