What is in the knife block?
The knives are in the knife block.
     src        edge_attr  dst
0      0   to the left of   10
1      0   to the left of    6
2      0   to the left of    5
3      0   to the left of   17
4      0   to the left of    7
..   ...              ...  ...
117   20   to the left of   14
118   21  to the right of   13
119   21  to the right of    9
120   21  to the right of    8
121   21  to the right of    0

[122 rows x 3 columns]