def upload(self, local_fn: str, remote_fn: str = '',
             dont_overwrite: bool = False):
    """Uploads given file to the task. If remote_fn is not specified, dumps it
    into task current directory with the same name.

    Args:
      local_fn: location of file locally
      remote_fn: location of file on task
      dont_overwrite: if True, will be no-op if target file exists
      """
    raise NotImplementedError()
Uploads given file to the task. If remote_fn is not specified, dumps it
    into task current directory with the same name.

    Args:
      local_fn: location of file locally
      remote_fn: location of file on task
      dont_overwrite: if True, will be no-op if target file exists