1d = {}
2print(d.setdefault(1))
3print(d.setdefault(1))
4print(d.setdefault(5, 42))
5print(d.setdefault(5, 1))
6print(d[1])
7print(d[5])
8d.pop(5)
9print(d.setdefault(5, 1))
10print(d[1])
11print(d[5])
12
13
14