Given the function def count_crossings_and_nestings(arcs): n = len(arcs) // 2crossings = 0 nestings = 0 for i in range(2 * n): for j in range(i+ 1, 2 * n): if arcs[i][0] < arcs[j][0] < arcs[i][1] < arcs[j][1]:, what does the function count_crossings_and_nestings do?