code: def _fetch_size(self, request: Request) -> int:
          '''Return size of file.
  
          Coroutine.
          '''
          try:
              size = yield from self._commander.size(request.file_path)
              return size
          except FTPServerError:
              returf _fetch_size(self, request: Request) -> int:
          '''Return size of file.
  
          Coroutine.
          '''
          try:
              size = yield from self._commander.size(request.file_path)
              return size
          except FTPServerError:
              return
docs: Return size of file.
  
          Coroutine.