Which kind of vehicle is yellow?
The vehicle is a bus.
    src        edge_attr  dst
0     0  to the right of    5
1     1  to the right of    5
2     2  to the right of    6
3     2   to the left of    4
4     3  to the right of    6
5     3  to the right of    5
6     4  to the right of    5
7     4  to the right of    2
8     5   to the left of    1
9     5   to the left of    0
10    5   to the left of    4
11    5   to the left of    3
12    5   to the left of    8
13    5  to the right of    6
14    6   to the left of    5
15    6   to the left of    3
16    6   to the left of    2
17    6   to the left of    7
18    7  to the right of    6
19    7   to the left of    8
20    8  to the right of    5
21    8  to the right of    7