code: def forward(self, x):
      y = self.encode(x)
      y_small = F.max_pool2d(y, kernel_size=2, stride=2)
      return y, y_small
  
imports: import torch
  import torch.nn
  import torch.nn.functional
label_desc: Use image node_id 2 for calling the StackEncoder obj's underlying member method code with example usage: obj.forward(x) and returns: y,  y_small