On which side is the book, the right or the left?
The book is on the left of the image.
     src        edge_attr  dst
0      0   to the left of   13
1      0   to the left of   16
2      0   to the left of   21
3      0   to the left of   18
4      0   to the left of   11
..   ...              ...  ...
102   21   to the left of   18
103   21   to the left of   17
104   21  to the right of    0
105   21  to the right of   12
106   21  to the right of   14

[107 rows x 3 columns]