What is the name of the vehicles to the left of the person in the train?
The vehicles are cars.
    src        edge_attr  dst
0     0   to the left of    3
1     0               by    2
2     0   to the left of    7
3     2            below    6
4     2      in front of    8
5     3  to the right of    5
6     3   to the left of    7
7     3   to the left of    4
8     3  to the right of    0
9     4               in    2
10    4  to the right of    3
11    4  to the right of    5
12    5   to the left of    7
13    5   to the left of    3
14    5   to the left of    4
15    6            above    2
16    7               by    3
17    7  to the right of    3
18    7  to the right of    0
19    7  to the right of    5
20    8           behind    2