在复现一个论文，参考的代码使用的是

import paddle.fluid as fluid
import paddle.v2 as paddle

# 涉及到的调用为
train_reader = paddle.batch(
        paddle.reader.shuffle(
            data2index(WORD_DICT, TAG_DICT, sentence_train, seq_train), 
            buf_size=500),
        batch_size=128)

trainer = fluid.Trainer(
        train_func=joint_extraction,
        place=place,
        optimizer_func = optimizer_program)

trainer.train(
    reader=train_reader,
    num_epochs=100,
    event_handler=event_handler_plot,
    feed_order=feed_order)

我使用的是1.8.0，原代码是0.14，我在API页查找相应的替换函数，修改为了

import paddle
import paddle.fluid as fluid

train_reader = fluid.io.batch(
    paddle.reader.shuffle(
        data2index(WORD_DICT, TAG_DICT, sentence_train, seq_train), 
        buf_size=500),
    batch_size=128)

但是关于Trainer一直找不到相关的说明，可否请paddle官方代为解答一下？