code: def _mask_transform(self, gt_image):
      target = np.asarray(gt_image, np.float32)
      target = self.id2trainId(target).copy()
      edge_mask = None
      if self.edge:
          edge_mask = F.mask_to_binary_edge(
              target, radius=1, num_classes=self.NUM_CLASSES
          )
  
      target = paddle.to_tensor(target)
  
      return target, edge_mask
  
file_path: PaddleSeg/contrib/DomainAdaptation/datasets/cityscapes_noconfig.py
imports: import os
  import random
  import numpy
  import collections.abc
  from PIL import Image, ImageOps, ImageFilter, ImageFile
  import paddle
  from paddle import io
  import paddleseg.transforms.functional
label_desc: Use image node_id 7 for calling the CityDataset obj's underlying member method code with example usage: obj._mask_transform(gt_image) and returns: target,  edge_mask