class_docstr: PyTorch model operator base
code: def __call__(
      self, img_tensor: torch.Tensor
  ) -> NamedTuple("Outputs", [("cnn", np.ndarray)]):
      Outputs = NamedTuple("Outputs", [("cnn", np.ndarray)])
      return Outputs(self._model(img_tensor).detach().numpy())
  
file_path: towhee/tests/unittests/mock_operators/pytorch_cnn_operator/pytorch_cnn_operator.py
imports: from typing import NamedTuple
  import numpy
  import torch
  import torchvision
  from towhee.operator import Operator
label_desc: Use image node_id 2 for calling the PytorchCnnOperator obj's underlying member method code with example usage: obj.__call__(img_tensor) and returns: Outputs