code: def _is_valid_video(
      f, extensions=(".mp4", ".avi", ".mov", ".rmvb", ".flv")
  ):
      return f.lower().endswith(extensions)
  
imports: import time
  import os
  import sys
  import ast
  import argparse
label_desc: Use image node_id 4 for calling a global function with example usage: _is_valid_video(f, extensions) and returns: f