Are there any doors?
Yes, there is a door.
    src        edge_attr  dst
0     0   to the left of    1
1     0   to the left of   19
2     1  to the right of    0
3     1  to the right of   20
4     2   to the left of   12
..  ...              ...  ...
64   19  to the right of   18
65   19  to the right of    7
66   20  to the right of   16
67   20  to the right of    9
68   20   to the left of    1

[69 rows x 3 columns]