What is on the branch?
The bird house is on the branch.
    src        edge_attr  dst
0     0   to the left of    4
1     1   to the left of    6
2     1   to the left of    5
3     1   to the left of    2
4     1   to the left of    3
5     2               on    3
6     2  to the right of    1
7     2   to the left of    6
8     3  to the right of    4
9     3  to the right of    1
10    4               on    6
11    4   to the left of    3
12    4  to the right of    0
13    4   to the left of    6
14    5  to the right of    1
15    5   to the left of    6
16    6  to the right of    4
17    6  to the right of    2
18    6  to the right of    1
19    6  to the right of    5