code: def get_instance_segmentation_model(num_classes):
      """Get an instance segmentation model.
  
      :param num_classes: Number of classes.
      :type num_classes: int
      :returns: Instance segmentation model.
      :rtype: torchvision.models.detection.faster_rcnn.FasterRCNN
      """
      # load an instance segmentation model pre-trained on COCO
      model = torchvision.models.detection.fasterrcnn_resnet50_fpn(
          pretrained=True
      )
      in_features = model.roi_heads.box_predictor.cls_score.in_features
      # replace the pre-trained head with a new one
      model.roi_heads.box_predictor = FastRCNNPredictor(
          in_features, num_classes
      )
      return model
  
imports: import logging
  import os
  import urllib.request
label_desc: Use image node_id 2 for calling a global function with example usage: get_instance_segmentation_model(num_classes) and returns: model