Which place is it, a pond or an ocean?
It is a pond.
    src        edge_attr  dst
0     0   to the left of    5
1     0   to the left of    6
2     3               of    4
3     5  to the right of    0
4     5   to the left of    7
5     6  to the right of    0
6     6   to the left of    7
7     7  to the right of    9
8     7  to the right of    5
9     7  to the right of    6
10    8               of    4
11    9   to the left of    7