contar la cantidad de caracteres diferentes que aparecen más de una vez en una cadena

def char_count(text):
  # create a hashtable that counts the character frequency
  char_frequency = {}
  # iterate through the characters in the text
  for char in list(text):
    # if the character is in the hashtable, increment the frequency
    if char in char_frequency:
      char_frequency[char] += 1
    # if not in the hashtable, insert the character and set the frequency to 1
    else:
      char_frequency[char] = 1
  # create a list that holds the characters that appear more than once and their counts
  duplicate_chars = []
  for key, value in char_frequency.items():
    # if the frequency is greater than 1, append the character and its frequency to the list
    if value > 1:
      duplicate_chars.append((key, value))
  # return the list
  return duplicate_chars