code: def estimate_inmemory_data_size(self) -> Optional[int]:
      return None
  
file_path: ray/python/ray/data/datasource/bigquery_datasource.py
imports: import logging
  from typing import List, Optional
  from ray.data._internal.util import _check_import
  from ray.data.block import Block, BlockMetadata
  from ray.data.datasource.datasource import Datasource, ReadTask
  from ray.util.annotations import PublicAPI
label_desc: Use image node_id 3 for calling the BigQueryDatasource obj's underlying member method code with example usage: obj.estimate_inmemory_data_size() and returns: None