class_docstr: A datasource that lets you read images.
class_docstr_tok: ["A","datasource","that","lets","you","read","images","."]
code: def _rows_per_file(self):
      return 1
  
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 3 for calling the ImageDatasource obj's underlying member method code with example usage: obj._rows_per_file() and returns: int