code: def file_list(self):
          
          log.info('Listing files')
          res = self.__exchange(LIST_FILES)
          res = res.split('\r\n')
          # skip first and last lines
          res = res[1:-1]
          files = []
          for line in res:
              files.append(line.split('\t'))
          return files
docs: list files on the device