class_docstr: 可以被输入到分类模型中的普通数据集
class_docstr_tok: ["\u53ef\u4ee5\u88ab\u8f93\u5165\u5230\u5206\u7c7b\u6a21\u578b\u4e2d\u7684\u666e\u901a\u6570\u636e\u96c6"]
code: def __len__(self):
      return self.num_of_data
  
file_path: fastNLP/tests/helpers/datasets/paddle_data.py
imports: import numpy
  from fastNLP.envs.imports import _NEED_IMPORT_PADDLE
label_desc: Use image node_id 2 for calling the PaddleNormalXYDataset obj's underlying member method code with example usage: obj.__len__() and returns: self