What color is the train, green or black?
The train is green.
    src        edge_attr  dst
0     1   to the left of    9
1     1  to the right of   19
2     1   to the left of   15
3     2  to the right of    3
4     2  to the right of    6
..  ...              ...  ...
59   19   to the left of   18
60   19   to the left of   15
61   19  to the right of   16
62   19   to the left of    9
63   19               at   10

[64 rows x 3 columns]