Is the sky clear?
Yes, the sky is clear.
    src        edge_attr  dst
0     0   to the left of    5
1     0  to the right of    8
2     1  to the right of    8
3     1   to the left of    5
4     1               by    8
5     2   to the left of    3
6     3  to the right of    2
7     3               in    6
8     4  to the right of    7
9     5  to the right of    7
10    5  to the right of    1
11    5  to the right of    0
12    7             near    9
13    7   to the left of    5
14    7               in    6
15    7   to the left of    4
16    8   to the left of    0
17    8   to the left of    1
18    9               in    6
19    9             near    7
20    9        flying in    6