What is the knife on?
The knife is on the dish.
    src        edge_attr  dst
0     0               on    3
1     2  to the right of   10
2     2  to the right of   13
3     4       sitting on   10
4     5  to the right of    7
5     6  to the right of   13
6     6  to the right of   10
7     7   to the left of    5
8     8          wearing    9
9     8          holding    5
10    8   to the left of   13
11    9   to the left of   13
12   10   to the left of    2
13   10   to the left of    6
14   10       sitting on   12
15   11               on    3
16   13  to the right of    9
17   13   to the left of    2
18   13   to the left of    6
19   13  to the right of    8