Python - Unflatten dict -

i have multi-dimensional dict:

a = {'a' : 'b', 'c' : {'d' : 'e'}} 

and written simple function flatten dict:

def __flatten(self, dictionary, level = []):     tmp_dict = {}     key, val in dictionary.items():         if type(val) == dict:             tmp_dict.update(self.__flatten(val, level + [key]))         else:             tmp_dict['.'.join(level + [key])] = val     return tmp_dict 

after call function dict a in result:

{'a' : 'b', 'c.d' : 'e'} 

now, after making few instructions on flattened dict need build new, multi-dimensional dict flattened. example:

>> unflatten({'a' : 0, 'c.d' : 1)) {'a' : 0, 'c' : {'d' : 1}} 

the problem have not have function unflatten :)
can this? have no idea how it.

edit:

another example:

{'a' : 'b', 'c.d.e.f.g.h.i.j.k.l.m.n.o.p.r.s.t.u.w' : 'z'} 

should after unflatten:

{'a': 'b', 'c': {'d': {'e': {'f': {'g': {'h': {'i': {'j': {'k': {'l': {'m': {'n': {'o': {'p': {'r': {'s': {'t': {'u': {'w': 'z'}}}}}}}}}}}}}}}}}}} 

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and another:

{'a' : 'b', 'c.d' : 'z', 'c.e' : 1} 

to:

{'a' : 'b', 'c' : {'d' : 'z', 'e' : 1}} 

this increases difficulty of task, know. thats why had problem , found no solution in hours..

def unflatten(dictionary):     resultdict = dict()     key, value in dictionary.iteritems():         parts = key.split(".")         d = resultdict         part in parts[:-1]:             if part not in d:                 d[part] = dict()             d = d[part]         d[parts[-1]] = value     return resultdict