How to make an element of a dict accumulate other elements in python

I have the following structure of python dictionary lists (let's call it dict1):

dict1 = {"word1": {'111.txt': 1, '112.txt': 3, '113.txt': 2},
         "word2": {'111.txt': 2, '112.txt': 2, '113.txt': 1},
         "word3": {'111.txt': 1, '113.txt': 1},
         "word4": {'111.txt': 3, '113.txt': 2},
         "word5": {'111.txt': 5, '113.txt': 1}}

and I would like to create a new dictionary (dict2), where I have the keys of dict1 and the sum of the elements of that key as its elements. Thus:

{'111.txt': 12, '112.txt': 5, '113.txt': 7}

I tried to do the following code below, however, it is only storing the last element of dict1 in dict2, that is, it is not accumulating the values of dict1

for i,j in dict1.items():
     for k,w in j.items():
            dict2[k] =+ j[k]

The output is as follows, it leaves only the last element of dict1, it is not accumulating the sum.

{'111.txt': 5, '112.txt': 2, '113.txt': 1}

Does anyone know what may be wrong in the code? Or do you have a better idea?

Solution

I believe the error is in the way you initialise dict2 but can't tell much since you haven't posted that part. This should work though:

dict1 = {"word1": {'111.txt': 1, '112.txt': 3, '113.txt': 2},
         "word2": {'111.txt': 2, '112.txt': 2, '113.txt': 1},
         "word3": {'111.txt': 1, '113.txt': 1},
         "word4": {'111.txt': 3, '113.txt': 2},
         "word5": {'111.txt': 5, '113.txt': 1}}

dict2 = dict()

for i, j in dict1.items():
    for k, w in j.items():
        dict2[k] = dict2.get(k, 0) + j[k]

print(dict2)

output:

{'112.txt': 5, '113.txt': 7, '111.txt': 12}