def get_intersection(l1, l2):
    """ Finds the intersection of 2 lists including common duplicates"""
    intersection_set = set(l1).intersection(set(l2))
    intersection_list = []
    for i in intersection_set:
        num = min(l1.count(i), l2.count(i))
        for j in range(num):
            intersection_list.append(i)
    return intersection_list
