class_docstr: CrypTensor class that uses plaintext PyTorch tensors as underlying backend.
  This class should be used for testing purposes.
code: def matmul(self, tensor):
      result = self.clone()
      tensor = getattr(tensor, "_tensor", tensor)
      result._tensor = result._tensor @ tensor
      return result
  
imports: import torch
  from crypten import CrypTensor, register_cryptensor
label_desc: Use image node_id 10 for calling the PyTorchTensor obj's underlying member method code with example usage: obj.matmul(tensor) and returns: result