class_docstr: Interface for defining a custom :class:`~ray.data.Dataset` datasource.
  
  To read a datasource into a dataset, use :meth:`~ray.data.read_datasource`.
class_docstr_tok: ["Interface","for","defining","a","custom",":","class",":","`","~ray.data.Dataset","`","datasource",".","To","read","a","datasource","into","a","dataset",",","use",":","meth",":","`","~ray.data.read_datasource","`","."]
docstr: Callback for when a write job fails.
  
  This is called on a best-effort basis on write failures.
  
  Args:
      write_results: The list of the write task result futures.
      error: The first error encountered.
      kwargs: Forward-compatibility placeholder.
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code: def on_write_failed(
      self,
      write_results: List[ObjectRef[WriteResult]],
      error: Exception,
      **kwargs,
  ) -> None:
      """Callback for when a write job fails.
  
      This is called on a best-effort basis on write failures.
  
      Args:
          write_results: The list of the write task result futures.
          error: The first error encountered.
          kwargs: Forward-compatibility placeholder.
      """
      pass
  
imports: import warnings
  from typing import Any, Callable, Iterable, List, Optional
  import numpy
  import ray
  from ray.data._internal.execution.interfaces import TaskContext
  from ray.data._internal.util import _check_pyarrow_version
  from ray.data.block import Block, BlockAccessor, BlockMetadata
  from ray.data.context import DataContext
  from ray.types import ObjectRef
  from ray.util.annotations import Deprecated, DeveloperAPI, PublicAPI
label_desc: Use image node_id 6 for calling the Datasource obj's underlying member method code with example usage: obj.on_write_failed(write_results, error) without return types