code: def add_cti_file(self, file_path: str):
          
          if not os.path.exists(file_path):
              self._logger.warning(
                  'Attempted to add {0} which does not exist.'.format(file_path)
              )
  
          if file_path not in self._cti_files:
              self._cti_files.append(file_path)
              self._logger.info(
                  'Added {0} to the CTI file list.'.format(file_path)
              )
docs: Adds a CTI file to work with to the CTI file list.
  
          :param file_path: Set a file path to the target CTI file.
  
          :return: None.