code: def is_dir(self):
      if self._is_dir is None:
          self._is_dir = oss_isdir(self._path)
      return self._is_dir
  
imports: import base64
  import json
  import os
  from ..base import path_type, stringify_path
  from ....utils import lazy_import
label_desc: Use image node_id 2 for calling the OSSFileEntry obj's underlying member method code with example usage: obj.is_dir() and returns: self