code: def select_from(self, parent_path):
          
          path_cls = type(parent_path)
          is_dir = path_cls.is_dir
          exists = path_cls.exists
          listdir = parent_path._accessor.listdir
          return self._select_from(parent_path, is_dir, exists, listdir)
docs: Iterate over all child paths of `parent_path` matched by this
          selector.  This can contain parent_path itself.