def METHOD_NAME():
    src = []
    tgt = []
    with open(src_dir, 'r', encoding='utf-8') as f:
        lines = f.readlines()
        for line in lines:
            src.append(line.strip('\n').lower())
    with open(tgt_dir, 'r', encoding='utf-8') as f:
        lines = f.readlines()
        for line in lines:
            tgt.append(line.strip('\n').lower())
    return src, tgt