What is the drink that the mug holds?
The drink is milk.
    src        edge_attr  dst
0     1   to the left of    7
1     3               on    0
2     5  to the right of    8
3     6   to the left of    8
4     7  to the right of   11
5     7  to the right of    1
6     8  to the right of    6
7     8   to the left of    5
8    11   to the left of    7
9    12       sitting on    0
10   13       sitting on    0
11   14       sitting in   15
12   15          holding   11