Multilevel Dictionary (Solution)

multilevel-dict-solution.py

#!/usr/bin/env python

import collections
import pprint

dict_factory = lambda: collections.defaultdict(dict_factory)
x = collections.defaultdict(dict_factory)
x['a']['b']['c']['d'] = 1
print x['a']['b']['c']['d']
print pprint.pformat(x)  # looks a bit messy, but it gives you the idea

"""
Sample output (the addresses [in hexadecimal] will likely be different):
1
defaultdict(<function <lambda> at 0x7f733afa6230>, {'a': defaultdict(<function <lambda> at 0x7f733afa6230>, {'b': defaultdict(<function <lambda> at 0x7f733afa6230>, {'c': defaultdict(<function <lambda> at 0x7f733afa6230>, {'d': 1})})})})
"""