input: Write a function to convert a given string to a list of integers. The string will be a comma-separated list of numbers. If the input is an empty string, the function should return an empty list.
  
  def to_int_list(s):
      return [int(x) for x in s.split(',')] if s else []
  
  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("")==[]
  assert to_int_list("42,0,7")==[42, 0, 7]
  assert to_int_list("99,100,200,300")==[99, 100, 200, 300]
output: def to_int_list(s):
      return [int(x) for x in s.split(',')] if s else []