class_docstr: CrypTensor class that uses plaintext PyTorch tensors as underlying backend.
  This class should be used for testing purposes.
code: def avg_pool2d(self, kernel_size, stride=None, padding=0):
      result = self.clone()
      result._tensor = torch.nn.functional.avg_pool2d(
          result._tensor, kernel_size, stride=stride, padding=padding
      )
      return result
  
imports: import torch
  from crypten import CrypTensor, register_cryptensor
label_desc: Use image node_id 15 for calling the PyTorchTensor obj's underlying member method code with example usage: obj.avg_pool2d(kernel_size, stride, padding) and returns: result