What is inside the cage?
The tree is inside the cage.
     src        edge_attr  dst
0      0  to the right of    7
1      0   to the left of    5
2      0  to the right of   14
3      0   to the left of   17
4      0   to the left of    4
..   ...              ...  ...
107   22   to the left of    0
108   22   to the left of   12
109   22  to the right of    6
110   22   to the left of   15
111   22   to the left of   17

[112 rows x 3 columns]