def read_dir_file(filename):
    """
    THIS FUNCTION HAS BEEN RETIRED AND IS NOT IN USE AT THE MOMENT
    Reads a symmetry direction file
    :param filename: Name of dir file
    :return: (x,y,z) of the symmetry axis
    """
    dirs = []
    try:
        with open(filename, 'r') as f:
            for fileline in f:
                line = fileline.split()
                result = float(line[0]), float(line[1]), float(line[2])
                dirs.append(result)
        if len(dirs) == 0:
            raise ValueError('provided dir file is empty')
        return dirs
    except Exception as e:
        raise ValueError('Invalid input for use-dir')
