Python dictionary traversal given path array

dictionary_traversal.py

from functools import reduce
import operator

# 4bb

k = ["a", "b", "c", "d"]
ar = {}
ar["a"] = {}
ar["a"]["b"] = {}
ar["a"]["b"]["c"] = {}
ar["a"]["b"]["c"]["d"] = "ThePrice"

k_sub = k[:-1]
reduce(operator.getitem,k_sub, ar)[k[-1]] = reduce(operator.getitem, k, ar) + "gogogo"
#>>> ar
# {'a': {'b': {'c': {'d': 'ThePricegogogo'}}}}