code: def test_partial_output(self):
      class PartialOut(torch.autograd.Function):
          @staticmethod
          def forward(ctx, input):
              ctx.save_for_backward(input)
              values, indices = torch.topk(input, 3)
              return values
  
      class Caller(torch.nn.Module):
          def forward(self, input):
              return PartialOut.apply(input)
  
      model = Caller()
      input = torch.ones(1, 5)
      run_model_test(self, model, input_args=(input,))
  
file_path: pytorch/test/onnx/test_autograd_funs.py
imports: import pytorch_test_common
  import torch
  from onnx_test_common import run_model_test
  from torch.onnx import OperatorExportTypes
  from torch.onnx._globals import GLOBALS
  from torch.onnx.utils import _model_to_graph
  from torch.testing._internal import common_utils
label_desc: Use image node_id 3 for calling the TestAutogradFuns obj's underlying member method code with example usage: obj.test_partial_output() and returns: values, PartialOut