thread safe multiprocess python dictionary example https://stackoverflow.com/a/46228938/51700

multi_process_dictionary.py

from multiprocessing import Process, Manager

manager = Manager()
d = manager.dict()

def f():
    d[1].append(4)
    # the __str__() method of a dict object invokes __repr__() on each of its items,
    # so explicitly invoking __str__() is required in order to print the actual list items
    print({k: str(v) for k, v in d.items()}

if __name__ == '__main__':
    d[1] = manager.list()
    p = Process(target=f)
    p.start()
    p.join()