nesting defaultdicts in an arbitrary depth

Question

I would like to nest an arbitrary number of defaultdicts like so:

from collections import defaultdict   
D = defaultdict( lambda:defaultdict(int) )

this works fine as described earlier.

Now I'm looking for the way/function to do this for an arbitrary depth: so for instance I'd like to have a function

def Gen_DDict( dim=3 ):
    "code I'm looking for"

that will return this for dim=3:

defaultdict( lambda : defaultdict( lambda : defaultdict(int) ) )

Answer 1

def genDDict(dim=3):
    if dim==1:
        return collections.defaultdict(int)
    else:
        return collections.defaultdict(lambda: genDDict(dim-1))

Output:

In [257]: d = genDDict(2)

In [258]: d[2][1]
Out[258]: 0