Are the cars to the left of the hydrant?
Yes, the cars are to the left of the hydrant.
   src        edge_attr  dst
0    0   to the left of    1
1    1   to the left of    7
2    1  to the right of    0
3    4  to the right of    5
4    5   to the left of    4
5    5  to the right of    6
6    6   to the left of    5
7    7  to the right of    1