Is this a black bus?
Yes, this is a black bus.
    src        edge_attr  dst
0     0               on    1
1     0               by    6
2     0   to the left of    9
3     1   to the left of    8
4     1   to the left of    9
5     2   to the left of    9
6     2               by    3
7     3               on    6
8     3               by    9
9     3               by    5
10    3   to the left of    9
11    4  to the right of    5
12    5   to the left of    4
13    5               by    6
14    5   to the left of    9
15    7           behind    9
16    7  to the right of    9
17    8               on    9
18    8               of    9
19    8  to the right of    1
20    9               on    6
21    9      in front of    7
22    9  to the right of    0
23    9  to the right of    1
24    9  to the right of    2
25    9  to the right of    3
26    9  to the right of    5
27    9   to the left of    7