Which side is the blue vehicle on, the right or the left?
The train is on the left of the image.
   src        edge_attr  dst
0    1   to the left of    7
1    2  to the right of    6
2    3  to the right of    6
3    6   to the left of    2
4    6   to the left of    3
5    7  to the right of    1