from typing import Iterable

list1 = ["toto", "titi", "tata", "titi"]
list2 = ["tutu", "titi", "tata", "tutu"]


def count_occurrences(input_list: Iterable) -> dict:
    result = {}
    for x in input_list:
        result[x] = result.get(x, 0) + 1
    return result


def get_diff(old_list: Iterable, new_list: Iterable) -> Iterable:
    old_counts = count_occurrences(old_list)
    new_counts = count_occurrences(new_list)

    result = []

    for element, old_count in old_counts.items():
        new_count = new_counts.get(element, 0)
        diff_count = new_count - old_count

        if diff_count < 0:
            for _ in range(-diff_count):
                result.append("del, \"%s\"" % element)

    for element, new_count in new_counts.items():
        old_count = old_counts.get(element, 0)
        diff_count = new_count - old_count

        if diff_count > 0 :
            for _ in range(diff_count):
                result.append("add, \"%s\"" % element)

    return result