List of competition files.

def competition_files(self):
    """List of competition files."""
    command = [
        "kaggle",
        "datasets" if "/" in self._competition_name else "competitions",
        "files",
        "-v",
        self._competition_name,
    ]
    output = _run_kaggle_command(command, self._competition_name)
    return sorted([
        line.split(",")[0] for line in output.split("\n")[1:] if line
    ])