code: def __len__(self) -> int:
      return len(self._data)
  
imports: from __future__ import annotations
  import operator
  import typing
  from typing import Any
  from typing import Callable
  from typing import Dict
  from typing import Iterator
  from typing import List
  from typing import Mapping
  from typing import Optional
  from typing import Tuple
  from typing import Type
label_desc: Use image node_id 7 for calling the BaseRow obj's underlying member method code with example usage: obj.__len__() and returns: len