code: def imageloader_iter(video_folder):
      # assume the video frames can be ordered by naming
      video_frames = os.listdir(video_folder)
      video_frames.sort()
  
      for frame_id, frame_path in enumerate(video_frames):
          frame = cv2.imread(os.path.join(video_folder, frame_path))
          yield frame_id, frame[:, :, ::-1]
  
file_path: gluon-cv/scripts/tracking/smot/demo.py
imports: import os
  import argparse
  import logging
  import numpy
  import cv2
  from gluoncv.model_zoo.smot import smot_tracker
  from gluoncv.model_zoo.smot.tracktors import GluonSSDMultiClassTracktor
label_desc: Use image node_id 4 for calling a global function with example usage: imageloader_iter(video_folder) without return types