What is the color of the long arrow?
The arrow is white.
   src        edge_attr  dst
0    1               on    6
1    1  to the right of    5
2    3   to the left of    6
3    4   to the left of    6
4    5   to the left of    1
5    5   to the left of    6
6    6  to the right of    4
7    6  to the right of    3
8    6  to the right of    5