code: def forward(self, x):
      short_cuts = []
      x = self.double_conv(x)
      for down_sample in self.down_sample_list:
          short_cuts.append(x)
          x = down_sample(x)
      return x, short_cuts
  
imports: import paddle
  import paddle.nn
  import paddle.nn.functional
  from paddleseg import utils
  from paddleseg.cvlibs import manager
  from paddleseg.models import layers
label_desc: Use image node_id 3 for calling the Encoder obj's underlying member method code with example usage: obj.forward(x) and returns: x,  short_cuts