What is in the briefcase?
The books are in the briefcase.
    src        edge_attr  dst
0     0               in    5
1     0   to the left of    8
2     0   to the left of    7
3     1   to the left of    4
4     2        on top of    0
5     2   to the left of    8
6     2   to the left of    7
7     4   to the left of    6
8     4  to the right of    1
9     4               of    5
10    5      filled with    8
11    5   to the left of   10
12    5      filled with    9
13    5      filled with    7
14    5      filled with    0
15    6  to the right of    4
16    7   to the left of   10
17    7  to the right of    9
18    7               in    5
19    7  to the right of    2
20    7  to the right of    0
21    8               in    5
22    8  to the right of    0
23    8  to the right of    9
24    8  to the right of    2
25    9               in    5
26    9   to the left of    7
27    9   to the left of    8
28   10  to the right of    5
29   10  to the right of    7
30   11               of    5