code: def _null_wrap_init(
      init: Callable[[KeyType], AggType]
  ) -> Callable[[KeyType], WrappedAggType]:
      """
      Wraps an accumulation initializer with null handling.
  
      The returned initializer function adds on a has_data field that the accumulator
      uses to track whether an aggregation is empty.
  
      Args:
          init: The core init function to wrap.
  
      Returns:
          A new accumulation initializer function that can handle nulls.
      """
  
      def _init(k: KeyType) -> AggType:
          a = init(k)
          # Initializing accumulation, so indicate that the accumulation doesn't represent
          # real data yet.
          return _wrap_acc(a, has_data=False)
  
      return _init
  
file_path: ray/python/ray/data/_internal/null_aggregate.py
imports: from types import ModuleType
  from typing import Any, Callable, Tuple, Union
  import numpy
  from ray.data.block import AggType, Block, KeyType, T, U
label_desc: Use image node_id 3 for calling a global function with example usage: _null_wrap_init(init) and returns: _init, _wrap_acc