code: def estimate_inmemory_data_size(self) -> Optional[int]:
      total_size = 0
      for sz in self._file_sizes:
          if sz is not None:
              total_size += sz
      return total_size
  
imports: import contextlib
  import logging
  from typing import Any, Callable, Dict, Iterable, List, Optional, Tuple, TYPE_CHECKING, Union
  import ray
  import urllib3
  from packaging import version
  from ray.data.block import Block
  from ray.data.context import DatasetContext
  from ray.data.datasource.binary_datasource import BinaryDatasource
  from ray.data.datasource.datasource import Datasource, ReadTask
  from ray.data.datasource.file_based_datasource import _check_pyarrow_version, _resolve_paths_and_filesystem, _S3FileSystemWrapper, _wrap_s3_serialization_workaround, BaseFileMetadataProvider, BlockOutputBuffer, DefaultFileMetadataProvider
  from ludwig.utils.fs_utils import get_bytes_obj_from_http_path, is_http
label_desc: Use image node_id 2 for calling the _BinaryIgnoreNoneTypeDatasourceReader obj's underlying member method code with example usage: obj.estimate_inmemory_data_size() and returns: total_size