Are there any hippoes?
Yes, there is a hippo.
     src        edge_attr  dst
0      0  to the right of   21
1      0  to the right of   24
2      2  to the right of   33
3      2  to the right of   34
4      2   to the left of   16
..   ...              ...  ...
228   34  to the right of   17
229   34   to the left of   10
230   34  to the right of    5
231   34   to the left of    4
232   34   to the left of    2

[233 rows x 3 columns]