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, minimum, and mean elements. If the given string is empty, the function should return None or any appropriate value indicating that no valid statistics can be calculated.
  
  def get_stats_for_string(string):
      if not string:
          return None
      num_elements = len(string)
      max_element = max(string)
      min_element = min(string)
      mean_element = sum(string.encode()) / num_elements
      return (max_element, min_element, mean_element)
  
  assert get_stats_for_string("abcdef") == ('f', 'a', 98.0)
  assert get_stats_for_string("zyxwvut") == ('z', 't', 113.57142857142857)
  assert get_stats_for_string("") == None
  assert get_stats_for_string("A") == ('A', 'A', 65.0)
output: def get_stats_for_string(string):
      if not string:
          return None
      num_elements = len(string)
      max_element = max(string)
      min_element = min(string)
      mean_element = sum(ord(char) for char in string) / num_elements
      return (max_element, min_element, mean_element)