class_docstr: A datasource that lets you read images.
class_docstr_tok: ["A","datasource","that","lets","you","read","images","."]
code: def estimate_inmemory_data_size(self) -> Optional[int]:
      total_size = 0
      for file_size in self._file_sizes():
          # NOTE: check if file size is not None, because some metadata provider
          # such as FastFileMetadataProvider does not provide file size information.
          if file_size is not None:
              total_size += file_size
      return total_size * self._encoding_ratio
  
imports: import io
  import logging
  import time
  from typing import TYPE_CHECKING, Iterator, List, Optional, Tuple, Union
  import numpy
  from ray.data._internal.delegating_block_builder import DelegatingBlockBuilder
  from ray.data._internal.util import _check_import
  from ray.data.block import Block, BlockMetadata
  from ray.data.datasource.file_based_datasource import FileBasedDatasource
  from ray.data.datasource.file_meta_provider import DefaultFileMetadataProvider
  from ray.util.annotations import DeveloperAPI
label_desc: Use image node_id 4 for calling the ImageDatasource obj's underlying member method code with example usage: obj.estimate_inmemory_data_size() and returns: unknown