docs: def read_digits(ctx, text):
      """
      Formats digits in text for reading in TTS
      """
      def chunk(value, chunk_size):
          return [value[i: i + chunk_size] for i in range(0, len(value), chunk_size)]
  
      text = conversions.to_string(text, ctx).strip()
      if not text:
          return ''
  
      # trim off the plus for phone numbers
      if text[0] == '+':
          text = text[1:]
  
      length = len(text)
  
      # ssn
      if length == 9:
          result = ' '.join(text[:3])
          result += ' , ' + ' '.join(text[3:5])
          result += ' , ' + ' '.join(text[5:])
          return result
  
      # triplets, most international phone numbers
      if length % 3 == 0 and length > 3:
          chunks = chunk(text, 3)
          return ' '.join(','.join(chunks))
  
      # quads, credit cards
      if length % 4 == 0:
          chunks = chunk(text, 4)
          return ' '.join(','.join(chunks))
  
      # otherwise, just put a comma between each number
      return ','.join(text)