Is the van to the right or to the left of the vehicle in the middle?
The van is to the right of the bus.
     src        edge_attr  dst
0      0  to the right of   21
1      0  to the right of    2
2      0  to the right of   29
3      0  to the right of   22
4      0   to the left of    8
..   ...              ...  ...
135   32   to the left of   16
136   32   to the left of   23
137   32  to the right of    3
138   32   to the left of    8
139   32  to the right of   13

[140 rows x 3 columns]