code: def estimate_inmemory_data_size(self):
      return None
  
imports: import argparse
  import json
  import time
  from typing import Dict, List, Any
  import pandas
  import pyarrow
  import numpy
  import ray
  from ray.data.block import BlockMetadata
  from ray.data.context import DataContext, DEFAULT_TARGET_MAX_BLOCK_SIZE
  from ray.data.datasource import Datasource, ReadTask, Reader
label_desc: Use image node_id 2 for calling the BlockReader obj's underlying member method code with example usage: obj.estimate_inmemory_data_size() and returns: None