Is the brown cow to the right or to the left of the bull that is in the grass?
The cow is to the left of the bull.
    src        edge_attr  dst
0     0   to the left of   21
1     0   to the left of   15
2     0   to the left of    2
3     0   to the left of   13
4     0   to the left of   12
..  ...              ...  ...
62   21  to the right of   13
63   21   to the left of   12
64   21  to the right of   20
65   21  to the right of    0
66   21   to the left of    6

[67 rows x 3 columns]