Are there any zebras?
No, there are no zebras.
    src        edge_attr  dst
0     1   to the left of    7
1     1  to the right of    6
2     1  to the right of    8
3     2  to the right of    6
4     2   to the left of    5
5     2  to the right of    8
6     4   to the left of    8
7     5  to the right of    8
8     5  to the right of    2
9     6   to the left of    8
10    6   to the left of    2
11    6   to the left of    1
12    7  to the right of    1
13    8   to the left of    1
14    8  to the right of    4
15    8   to the left of    5
16    8  to the right of    6
17    8   to the left of    2