code: def convert_sbcs_model(old_model, alphabet):
      
      # Setup tables necessary for computing transition frequencies for model
      char_to_order = {i: order
                       for i, order in enumerate(old_model['char_to_order_map'])}
      pos_ratio = old_model['typical_positive_ratio']
      keep_ascii_letters = old_model['keep_english_letter']
  
      curr_model = SingleByteCharSetModel(charset_name=old_model['charset_name'],
                                          language=old_model['language'],
                                          char_to_order_map=char_to_order,
                                          # language_model is filled in later
                                          language_model=None,
                                          typical_positive_ratio=pos_ratio,
                                          keep_ascii_letters=keep_ascii_letters,
                                          alphabet=alphabet)
      return curr_model
docs: Create a SingleByteCharSetModel object representing the charset.