code: def forward(self, x_big, x):
      N, C, H, W = x_big.size()
      y = F.interpolate(x, size=(H, W), mode="bilinear")
      y = torch.cat([y, x_big], 1)
      y = self.decode(y)
      return y
  
imports: import torch
  import torch.nn
  import torch.nn.functional
label_desc: Use image node_id 2 for calling the StackDecoder obj's underlying member method code with example usage: obj.forward(x_big, x) and returns: y