class_docstr: 可以被输入到分类模型中的普通数据集
code: def __getitem__(self, item):
      return {
          "x": torch.tensor([self._data[item]], dtype=torch.float),
          "y": torch.tensor([self._data[item]], dtype=torch.float),
      }
  
imports: from functools import reduce
  from numpy import dtype
  from fastNLP.envs.imports import _NEED_IMPORT_TORCH
label_desc: Use image node_id 3 for calling the TorchNormalXYDataset obj's underlying member method code with example usage: obj.__getitem__(item) and returns: dict