docs: def relpath(path, start=None):
      """
      Return a relative file path to path either from the
      current directory or from an optional start directory.
  
      For storage objects, "path" and "start" are relative to
      storage root.
  
      "/" are not stripped on storage objects path. The ending slash is required
      on some storage to signify that target is a directory.
  
      Equivalent to "os.path.relpath".
  
      Args:
          path (path-like object): Path or URL.
          start (path-like object): Relative from this optional directory.
              Default to "os.curdir" for local files.
  
      Returns:
          str: Relative path.
      """
      relative = get_instance(path).relpath(path)
      if start:
          # Storage relative path
          # Replaces "\" by "/" for Windows.
          return os_path_relpath(relative, start=start).replace('\\', '/')
      return relative