What color is the vehicle near the tree?
The train is black.
    src        edge_attr  dst
0     1  to the right of    4
1     1   to the left of    5
2     2  to the right of    4
3     3  to the right of    4
4     3   to the left of    6
5     3   to the left of    5
6     4             near    5
7     4   to the left of    2
8     4   to the left of    1
9     4   to the left of    5
10    4   to the left of    3
11    4   to the left of    6
12    4          next to    5
13    5  to the right of    4
14    5  to the right of    3
15    5             near    4
16    5  to the right of    1
17    6  to the right of    3
18    6  to the right of    4
19    6   to the left of    7
20    7  to the right of    6