code: def forward(self, x, y):
      return x, y
  
imports: import pytest
  from art.defences.preprocessor.preprocessor import PreprocessorPyTorch
  from tests.utils import ARTTestException
label_desc: Use image node_id 1 for calling the DummyPreprocessorPyTorch obj's underlying member method code with example usage: obj.forward(x, y) and returns: x,  y