def prepare_directories(args, run_name):
    if not os.path.isdir(args.data_path):
        raise Exception("Invalid data path. No such directory")

    if not os.path.isdir(args.log_path):
        os.makedirs(args.log_path)

    if args.pretrained_path:
        if not os.path.isdir(args.pretrained_path) or \
                not os.path.isdir(os.path.join(args.pretrained_path, 'states')):
            raise Exception("Invalid path. No such directory with pretrained model")

    else:
        exp_path = os.path.join(args.log_path, run_name)
        os.makedirs(exp_path)
        os.makedirs(os.path.join(exp_path, 'samples'))
        os.makedirs(os.path.join(exp_path, 'states'))
        os.makedirs(os.path.join(exp_path, 'tensorboard_logs'))