code: def forward(self, x, y=None) -> torch.Tensor:
      out = self.linear1(x)
      if y is not None:
          out = x + self.linear2(y)
      return out.sum(-1)
  
imports: import torch
  import torch.nn
  import pytest
  from allennlp.common.params import Params
  from allennlp.common.testing import multi_device
  from allennlp.nn.checkpoint.checkpoint_wrapper import CheckpointWrapper, TorchCheckpointWrapper
label_desc: Use image node_id 2 for calling the SubmoduleWithKwargs obj's underlying member method code with example usage: obj.forward(x, y) and returns: out