Hallar el promedio de los que son mayores a 500 y el promedio de los que son menores a 500

def average(marks):
  total = 0
  count = 0
  for m in marks:
    if m >= 500:
      total += m
      count += 1
  return total / count

def average_w(marks):
  total = 0
  count = 0
  for m in marks:
    if m < 500:
      total += m
      count += 1
  return total / count

marks = [80, 200, 500, 300, 90, 600, 100, 1000, 220]