Which color is the sky?
The sky is white.
   src        edge_attr  dst
0    1   to the left of    4
1    1  to the right of    8
2    1   to the left of    6
3    2   to the left of    5
4    4  to the right of    1
5    5  to the right of    2
6    6  to the right of    1
7    8   to the left of    1