code: def merge_strings_files(old_strings_file, new_strings_file):
      
      old_localizable_dict = generate_localization_key_to_entry_dictionary_from_file(old_strings_file)
      output_file_elements = []
  
      f = open_strings_file(new_strings_file, "r+")
  
      for header_comment, comments, key, value in extract_header_comment_key_value_tuples_from_file(f):
          if len(header_comment) > 0:
              output_file_elements.append(Comment(header_comment))
  
          localize_value = value
          if key in old_localizable_dict:
              localize_value = old_localizable_dict[key].value
  
          output_file_elements.append(LocalizationEntry(comments, key, localize_value))
  
      f.close()
  
      write_file_elements_to_strings_file(old_strings_file, output_file_elements)
docs: Merges the old strings file with the new one.
  
      Args:
          old_strings_file (str): The path to the old strings file (previously produced, and possibly altered)
          new_strings_file (str): The path to the new strings file (newly produced).