my_flatten({{1}, 2, {{3, 4}, 5}, {{{}}}, {{{6}}}, 7, 8, {}})

on my_flatten(aList)
    if class of aList is not list then
        return {aList}
    else if length of aList is 0 then
        return aList
    else
        return my_flatten(first item of aList) & (my_flatten(rest of aList))
    end if
end my_flatten