What vehicle is the couple in?
The couple is in the train.
    src        edge_attr  dst
0     0  to the right of   17
1     1   to the left of    5
2     1   to the left of    2
3     1   to the left of    8
4     1   to the left of   17
..  ...              ...  ...
62   18  to the right of    7
63   18  to the right of   17
64   18  to the right of   15
65   19   to the left of    3
66   19   to the left of   17

[67 rows x 3 columns]