def METHOD_NAME(self, filename: str) -> None:
    """Pretend that a local file was downloaded from the internet.
    Args:
        filename: path to a local file to import.
    """
    try:
        fileobj = open(filename, "rb")  # pylint: disable=consider-using-with
    except OSError as e:
        message.error(
            "blockutils: Error while reading {}: {}".format(filename, e.strerror)
        )
        return
    download = FakeDownload(fileobj)
    self._in_progress.append(download)
    self._on_download_finished(download)