def METHOD_NAME():
    src = []
    tgt = []
    if enable_debug:
        part_file = './debug.txt'
        part_file = '/share/project/ldwang/data/pile/train/00.txt'
    path = '/share/project/ldwang/data/pile/train/'
    lines_count = 0
    # if True: # enable_debug
    for part_file in os.listdir(path):
        filename = path+part_file
        # filename = part_file # enable_debug
        print('*'*20, "filename", filename)
        with open(filename, 'r', encoding='utf-8') as f:
            lines = f.readlines()
            for line in lines:
                lines_count += 1
                src.append(line.strip('\n').lower())
                if lines_count%10000==1:
                    print('*'*20, 'lines_count', lines_count)
    return src, src