On which side of the picture is the tray?
The tray is on the left of the image.
    src        edge_attr  dst
0     0               in   12
1     0   to the left of   13
2     1   to the left of   18
3     1   to the left of   17
4     2  to the right of   13
..  ...              ...  ...
85   18  to the right of   12
86   18   to the left of   11
87   18   to the left of    6
88   18  to the right of    1
89   19   to the left of   15

[90 rows x 3 columns]