code: def _is_valid_video(
      f, extensions=(".mp4", ".avi", ".mov", ".rmvb", "flv")
  ):
      return f.lower().endswith(extensions)
  
imports: import os
  import sys
  import cv2
  import glob
  import numpy
  from collections import OrderedDict, defaultdict
  from .dataset import DetDataset, _make_dataset, _is_valid_file
  from ppdet.core.workspace import register, serializable
  from ppdet.utils.logger import setup_logger
label_desc: Use image node_id 1 for calling a global function with example usage: _is_valid_video(f, extensions) and returns: f