code: def forward(self, inputs):
      x1, _ = self.down1(inputs)
      _, x2 = self.down2(x1)
      _, x3 = self.down3(x2)
      _, x4 = self.down4(x3)
      _, x5 = self.down5(x4)
  
      x = self.up4(x4, x5)
      x = self.up3(x3, x)
      x = self.up2(x2, x)
      x = self.up1(x1, x)
      return x
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import paddle
  from paddle import nn
  import numpy
  import cv2
label_desc: Use image node_id 2 for calling the UNet obj's underlying member method code with example usage: obj.forward(inputs) and returns: x