input: Write a function to calculate the maximum, minimum, and mean number of elements in a given string. The function should return a tuple containing the maximum element, the minimum element, and the mean element of the string. If the string is empty, return (0, 0, 0).
  assert get_stats_for_string("abcdef") == ('f', 'a', (ord('a') + ord('b') + ord('c') + ord('d') + ord('e') + ord('f')) / 6)
  assert get_stats_for_string("12345") == ('5', '1', (int('1') + int('2') + int('3') + int('4') + int('5')) / 5)
  assert get_stats_for_string("Aa") == ('a', 'A', (ord('A') + ord('a')) / 2)
  assert get_stats_for_string("") == (0, 0, 0)
output: def get_stats_for_string(s):
      if not s:
          return (0, 0, 0)
      max_char = max(s)
      min_char = min(s)
      mean_value = sum(ord(c) for c in s) / len(s)
      return (max_char, min_char, mean_value)