code: def write_block_to_file(
      self, block: BlockAccessor, file: "pyarrow.NativeFile"
  ):
      value = block.to_numpy(self.column)
      np.save(file, value)
  
file_path: ray/python/ray/data/datasource/numpy_datasink.py
imports: import numpy
  import pyarrow
  from ray.data.block import BlockAccessor
  from ray.data.datasource.file_datasink import BlockBasedFileDatasink
label_desc: Use image node_id 2 for calling the _NumpyDatasink obj's underlying member method code with example usage: obj.write_block_to_file(block, file) without return types