What is the right way to check mp.managers.DictProxy' size?

I'm trying to learn multiprocessing and keep the memory usage low, so I'd like to check the size of my objects now and then. I'm using a mp.managers.DictProxy to store results from multiple mp.Process() 'workers'(?) that put their results in an output mp.Queue().

I tried to see what size the dictionary got, but it kept returning 56 when tried to test it.

EDIT: after testing it in python 3.9.7 (same device) the output now magically is 48.

import sys
import multiprocessing as mp

if __name__ == '__main__':   # needed if running on windows
    manager = mp.Manager()

    result_storage = manager.dict({k:k for k in range(100000)})

    print(sys.getsizeof(result_storage))
    # print USED to be 56 for me when i created this question
    # print is now 48 consistently. same device. I didn't record the previous python version
    # current python version is 3.9.7

    print(sys.getsizeof(result_storage.copy()))
    # prints 5242968

I've tried to print(sys.getsizeof(result_storage.copy())). That returned 5242976 5242968 Can I reliably use this to check the size or is there a better way? I've never used .copy() and I don't know what the impact is. The docs are beyond me.