class_docstr: Support MMOCR object detection models.
  Refer to https://github.com/open-mmlab/mmocr
code: def image_valid_num_key(self):
      return f"{self.prefix}_{IMAGE_VALID_NUM}"
  
file_path: autogluon/multimodal/src/autogluon/multimodal/models/mmocr_text_detection.py
imports: import logging
  from typing import Optional
  from torch import nn
  from ..constants import AUTOMM, BBOX, COLUMN, COLUMN_FEATURES, FEATURES, IMAGE, IMAGE_VALID_NUM, LABEL, LOGITS, MASKS
  from .utils import assign_layer_ids, get_column_features, get_mmocr_config_and_model, get_model_head
label_desc: Use image node_id 3 for calling the MMOCRAutoModelForTextDetection obj's underlying member method code with example usage: obj.image_valid_num_key() and returns: self, str, IMAGE_VALID_NUM