code: def forward(self, x, y):
      self.args.append((x, y))
      with chainer.using_device(backend.get_device_from_array(x, y)):
          chainer.report({"loss": x.sum() + y.sum()}, self)
  
imports: import unittest
  import numpy
  import chainer
  from chainer import backend
  from chainer.backends import _cpu
  from chainer import dataset
  from chainer import iterators
  from chainer import testing
  from chainer.training import extensions
label_desc: Use image node_id 2 for calling the DummyModelTwoArgs obj's underlying member method code with example usage: obj.forward(x, y) without return types