Fix language inference in generate.py

def load_with_check(path, load_splits, src=None, dst=None):

    """Loads the train, valid, and test sets from the specified folder

    and check that training files exist."""

    """Loads specified data splits (e.g., test, train or valid) from the

    specified folder and check that files exist."""

    def find_language_pair(files):

        for split in load_splits:

            for filename in files:

                parts = filename.split('.')

            if parts[0] == 'train' and parts[-1] == 'idx':

                if parts[0] == split and parts[-1] == 'idx':

                    return parts[1].split('-')

    def train_file_exists(src, dst):

        filename = 'train.{0}-{1}.{0}.idx'.format(src, dst)

    def split_exists(split, src, dst):

        filename = '{0}.{1}-{2}.{1}.idx'.format(split, src, dst)

        return os.path.exists(os.path.join(path, filename))

    if src is None and dst is None:

        # find language pair automatically

        src, dst = find_language_pair(os.listdir(path))

    elif train_file_exists(src, dst):

        # check for src-dst langcode

        pass

    elif train_file_exists(dst, src):

        # check for dst-src langcode

    if not split_exists(load_splits[0], src, dst):

        # try reversing src and dst

        src, dst = dst, src

    else:

        raise ValueError('training file not found for {}-{}'.format(src, dst))

    for split in load_splits:

        if not split_exists(load_splits[0], src, dst):

            raise ValueError('Data split not found: {}-{} ({})'.format(

                src, dst, split))

    dataset = load(path, load_splits, src, dst)

    return dataset