How do I merge lists in Python across multiple processes?

import multiprocessing

def merge_lists(proc_id, list_to_merge, result_list):
    for item in list_to_merge:
        result_list.append(item)

if __name__ == "__main__":
    manager = multiprocessing.Manager()
    result_list = manager.list()  # Create a shared list

    # Example input lists
    lists_to_merge = [
        [1, 2, 3],
        [4, 5],
        [6, 7, 8, 9]
    ]

    processes = []
    
    for lst in lists_to_merge:
        p = multiprocessing.Process(target=merge_lists, args=(1, lst, result_list))
        processes.append(p)
        p.start()

    for p in processes:
        p.join()

    # Convert result_list back to a regular list
    merged_list = list(result_list)
    print(merged_list)  # Output: [1, 2, 3, 4, 5, 6, 7, 8, 9]