Python Nested Dictionary

nested_dict.py

class Nil(object):
    def __getitem__(self, key):
        return Nil()
    def __nonzero__(self):
        return False


class NestedDict(dict):
    def __init__(self, *args, **kwargs):
        self.update(*args, **kwargs)
    def __missing__(self, key):
        return Nil()
    def __setitem__(self, key, val):
        if isinstance(val, dict): val = NestedDict(val)
        dict.__setitem__(self, key, val)
    def update(self, *args, **kwargs):
        for k, v in dict(*args, **kwargs).iteritems():
            self[k] = v

x = NestedDict({ '1': { '2': { '3': {'4': { '5': 'eran' }}}} })
if x['1']['2']['impossible!']:
    print 'Its impossible we print here!'
else:
    print 'all good'