code: def forward(self, s0, s1):
      # s0, s1 are the outputs of previous previous cell and previous cell, respectively.
      tensors = [self.preproc0(s0), self.preproc1(s1)]
      for node in self.mutable_ops:
          cur_tensor = node(tensors)
          tensors.append(cur_tensor)
  
      output = torch.cat(tensors[2:], dim=1)
      return output
  
imports: from collections import OrderedDict
  import torch
  import torch.nn
  import ops
  from nni.retiarii.nn.pytorch import LayerChoice, InputChoice
label_desc: Use image node_id 2 for calling the Cell obj's underlying member method code with example usage: obj.forward(s0, s1) and returns: output