input: Write a python function to convert a list of integers to a comma-separated string.
  assert list_to_comma_separated_string([1, 8, 10, 15, 12]) == "1, 8, 10, 15, 12"
  assert list_to_comma_separated_string([5, 3, 9]) == "5, 3, 9"
  assert list_to_comma_separated_string([0, -1, -5]) == "0, -1, -5"
output: def list_to_comma_separated_string(lst):
      return ', '.join(map(str, lst))