def double_sort(lst):
    no_of_elements = len(lst)
    for _ in range(
        0, int(((no_of_elements - 1) / 2) + 1)
    ):  # we don't need to traverse to end of list as
        for j in range(0, no_of_elements - 1):
            if (
                lst[j + 1] < lst[j]
            ):  # applying bubble sort algorithm from left to right (or forwards)
                temp = lst[j + 1]
                lst[j + 1] = lst[j]
                lst[j] = temp
            if (
                lst[no_of_elements - 1 - j] < lst[no_of_elements - 2 - j]
            ):  # applying bubble sort algorithm from right to left (or backwards)
                temp = lst[no_of_elements - 1 - j]
                lst[no_of_elements - 1 - j] = lst[no_of_elements - 2 - j]
                lst[no_of_elements - 2 - j] = temp
    return lst