code: def __init__(self):
      super(UNet, self).__init__()
      self.down1 = Encoder(num_channels=3, num_filters=16)
      self.down2 = Encoder(num_channels=16, num_filters=32)
      self.down3 = Encoder(num_channels=32, num_filters=64)
      self.down4 = Encoder(num_channels=64, num_filters=128)
      self.down5 = Encoder(num_channels=128, num_filters=256)
  
      self.up1 = Decoder(32, 16)
      self.up2 = Decoder(64, 32)
      self.up3 = Decoder(128, 64)
      self.up4 = Decoder(256, 128)
      self.out_channels = 16
  
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 1 to create a new UNet object from inherited base classes: nn with example: obj = UNet()