input: Write a function that converts a given string into a list of integers. The string contains numbers separated by commas. If the input string is empty, return an empty list.
  
  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("")==[]
  assert to_int_list("7")==[7]
  assert to_int_list("1,2,3,a")==[1, 2, 3, 'a']
output: def to_int_list(s):
      if s == "":
          return []
      try:
          return [int(x) for x in s.split(',')]
      except ValueError:
          return [x if not x.isdigit() else int(x) for x in s.split(',')]