class_docstr: PyOD Dataset class for PyTorch Dataloader
      
code: def __len__(self):
      return self.X.shape[0]
  
imports: from __future__ import division
  from __future__ import print_function
  import numpy
  import torch
  from sklearn.utils import check_array
  from sklearn.utils.validation import check_is_fitted
  from torch import nn
  from .base import BaseDetector
  from ..utils.stat_models import pairwise_distances_no_broadcast
  from ..utils.torch_utility import get_activation_by_name
label_desc: Use image node_id 2 for calling the PyODDataset obj's underlying member method code with example usage: obj.__len__() and returns: self