class_docstr: The OCRNet implementation based on PaddlePaddle.
  The original article refers to
      Yuan, Yuhui, et al. "Object-Contextual Representations for Semantic Segmentation"
      (https://arxiv.org/pdf/1909.11065.pdf)
  Args:
      num_classes (int): The unique number of target classes.
      backbone_indices (list): A list indicates the indices of output of backbone.
          It can be either one or two values, if two values, the first index will be taken as
          a deep-supervision feature in auxiliary layer; the second one will be taken as
          input of pixel representation. If one value, it is taken by both above.
      ocr_mid_channels (int, optional): The number of middle channels in OCRHead. Default: 512.
      ocr_key_channels (int, optional): The number of key channels in ObjectAttentionBlock. Default: 256.
      align_corners (bool): An argument of F.interpolate. It should be set to False when the output size of feature
          is even, e.g. 1024x512, otherwise it is True, e.g. 769x769.  Default: False.
      pretrained (str, optional): The path or url of pretrained model. Default: None.
code: def forward(self, x: paddle.Tensor) -> paddle.Tensor:
      feats = self.backbone(x)
      feats = [feats[i] for i in self.backbone_indices]
      logit_list = self.head(feats)
      logit_list = [
          F.interpolate(
              logit,
              x.shape[2:],
              mode="bilinear",
              align_corners=self.align_corners,
          )
          for logit in logit_list
      ]
      return logit_list
  
imports: import os
  from typing import List
  import paddle
  import numpy
  import paddle.nn
  import paddle.nn.functional
  from paddlehub.module.module import moduleinfo
  import paddlehub.vision.segmentation_transforms
  from paddlehub.module.cv_module import ImageSegmentationModule
  import ocrnet_hrnetw18_cityscapes.layers
  from ocrnet_hrnetw18_cityscapes.hrnet import HRNet_W18
label_desc: Use image node_id 3 for calling the OCRNetHRNetW18 obj's underlying member method code with example usage: obj.forward(x) and returns: logit_list