code: def __init__(self, num_classes=91, **kwargs):
      backbone = resnet_fpn_backbone("resnet50", False)
      super(MASKRCNNObjectDetector, self).__init__(
          backbone, num_classes, **kwargs
      )
  
imports: from torchvision.models.detection.mask_rcnn import MaskRCNN
  from torchvision.models.detection.backbone_utils import resnet_fpn_backbone
label_desc: Use image node_id 1 to create a new MASKRCNNObjectDetector object from inherited base classes: MaskRCNN with example: obj = MASKRCNNObjectDetector(num_classes)