class_docstr: This is the Detection Model training class, which allows you to train object detection models
  on image datasets that are in YOLO format, using the YOLOv3.
code: def __load_model(self) -> None:
      try:
          state_dict = torch.load(
              self.__model_path, map_location=self.__device
          )
          # check against cases where number of classes differs, causing the
          # channel of the convolutional layer just before the detection layer
          # to differ.
          new_state_dict = {
              k: v
              for k, v in state_dict.items()
              if k in self.__model.state_dict().keys()
              and v.shape == self.__model.state_dict()[k].shape
          }
          self.__model.load_state_dict(new_state_dict, strict=False)
          print("=" * 20)
          print("Pretrained YOLOv3 model loaded to initialize weights")
          print("=" * 20)
      except Exception as e:
          print("=" * 20)
          print(
              "pretrained weight loading failed. Defaulting to using random weight."
          )
          print("=" * 20)
  
imports: import os
  import time
  import math
  import json
  import warnings
  from typing import List, Union, Tuple, Dict
  from collections import defaultdict
  import numpy
  from PIL import Image
  import cv2
  import torch
  from torch.cuda import amp
  from torch.utils.data import DataLoader
  from torch.optim import SGD, lr_scheduler
  from tqdm import tqdm
  from .yolo.dataset import LoadImagesAndLabels
  from .yolo.custom_anchors import generate_anchors
  from .yolo.compute_loss import compute_loss
  from .yolo import validate
  from ...yolov3.tiny_yolov3 import YoloV3Tiny
  from ...yolov3.yolov3 import YoloV3
  from ...yolov3.utils import draw_bbox_and_label, get_predictions, prepare_image
  from ...backend_check.model_extension import extension_check
label_desc: Use image node_id 3 for calling the DetectionModelTrainer obj's underlying member method code with example usage: obj.__load_model() without return types