code: def forward(self, x, skip):
      out = self.convTrans(x)
      out = center_crop(out, skip.size(2), skip.size(3))
      out = torch.cat([out, skip], 1)
  
      return out
  
imports: import torch
  import torch.functional
  import torch.nn
label_desc: Use image node_id 2 for calling the TransitionUp obj's underlying member method code with example usage: obj.forward(x, skip) and returns: out