1）PaddlePaddle版本：2.2
   2）CPU：AMD3500U
   3）GPU：无
   4）系统环境：windows10， Python版本3.7

WARNING: Detect dataset only contains single fileds, return format changed since Paddle 2.1. In Paddle <= 2.0, DataLoader add a list surround output data(e.g. return [data]), and in Paddle >= 2.1, DataLoader return the single filed directly (e.g. return data).

paddle已经是2.2版本的， 但是__getitem__返回数据不加 [] 就会WARNING

啥时候修复错误

快速复现该WARNING：

import numpy as np
import paddle
from paddle.io import DataLoader

# define a random dataset

class Dataset(paddle.io.Dataset):
    def __init__(self, images):
        self.images = images[:]

    def __getitem__(self, index):
        return self.images[index].astype('float32')

# return [self.images[index].astype('float32')]

    def __len__(self):
        return len(self.images)

images = paddle.rand((100,224,224))
i_query_data = Dataset( images)
loader = DataLoader(i_query_data,
                    batch_size=64,
                    shuffle=True,
                    drop_last=True,
                    num_workers=0)

for i,image in enumerate(loader()):
    print(i,image)
    break