code: def write_block_to_file(
      self, block: BlockAccessor, file: "pyarrow.NativeFile"
  ):
      file.write(b"")
  
imports: import os
  from typing import Any, Dict
  import pyarrow
  import pytest
  from pyarrow.fs import LocalFileSystem
  import ray
  from ray.data.block import BlockAccessor
  from ray.data.datasource import BlockBasedFileDatasink, RowBasedFileDatasink
label_desc: Use image node_id 1 for calling the MockFileDatasink obj's underlying member method code with example usage: obj.write_block_to_file(block, file) without return types