Which kind of device is this?
This is a phone.
   src        edge_attr  dst
0    0   to the left of    2
1    0   to the left of    1
2    1   to the left of    3
3    1  to the right of    0
4    2   to the left of    3
5    2   to the left of    4
6    2  to the right of    0
7    3  to the right of    2
8    3  to the right of    1
9    4  to the right of    2