code: def _get_size(self):
      if self._size is None:
          self._size = int(oss_stat(self._path)["size"])
      return self._size
  
file_path: mars/mars/lib/filesystem/_oss_lib/handle.py
imports: from io import IOBase
  from ....utils import lazy_import
  from .common import parse_osspath, oss_stat
label_desc: Use image node_id 5 for calling the OSSIOBase obj's underlying member method code with example usage: obj._get_size() and returns: self