input: Write a function that converts a given string to a list of integers. The input string contains numbers separated by commas. Return the list of integers.
  
  def to_int_list(s):
      return [int(x) for x in s.split(',')]
  
  assert to_int_list("1,2,3,4,5")==[1, 2, 3, 4, 5]
  assert to_int_list("10,20,30")==[10, 20, 30]
  assert to_int_list("0,0,0")==[0, 0, 0]
  assert to_int_list("5,4,3,2,1")==[5, 4, 3, 2, 1]
  assert to_int_list("")==[]
output: def to_int_list(s):
      return [int(x) for x in s.split(',')]