code: def VShadowPathSpecGetStoreIndex(path_spec):
    
    store_index = getattr(path_spec, 'store_index', None)
  
    if store_index is None:
      location = getattr(path_spec, 'location', None)
  
      if location is None or not location.startswith('/vss'):
        return None
  
      store_index = None
      try:
        store_index = int(location[4:], 10) - 1
      except (TypeError, ValueError):
        pass
  
      if store_index is None or store_index < 0:
        return None
  
    return store_index
docs: Retrieves the store index from the path specification.
  
    Args:
      path_spec (PathSpec): path specification.
  
    Returns:
      int: store index or None if not available.