class_docstr: Represents a single transform function in a MapTransformer.
class_docstr_tok: ["Represents","a","single","transform","function","in","a","MapTransformer","."]
docstr: Args:
      callable: the underlying Python callable object.
      input_type: the type of the input data.
      output_type: the type of the output data.
docstr_tok: ["Args",":","callable",":","the","underlying","Python","callable","object",".","input_type",":","the","type","of","the","input","data",".","output_type",":","the","type","of","the","output","data","."]
code: def __init__(
      self,
      input_type: MapTransformFnDataType,
      output_type: MapTransformFnDataType,
  ):
      """
      Args:
          callable: the underlying Python callable object.
          input_type: the type of the input data.
          output_type: the type of the output data.
      """
      self._callable = callable
      self._input_type = input_type
      self._output_type = output_type
      self._target_max_block_size = None
  
imports: import itertools
  from abc import abstractmethod
  from enum import Enum
  from typing import Any, Callable, Dict, Iterable, List, Optional, TypeVar, Union
  from ray.data._internal.block_batching.block_batching import batch_blocks
  from ray.data._internal.execution.interfaces.task_context import TaskContext
  from ray.data._internal.output_buffer import BlockOutputBuffer
  from ray.data.block import Block, BlockAccessor, DataBatch
label_desc: Use image node_id 1 to create a new MapTransformFn object  with example: obj = MapTransformFn(input_type, output_type)