code: def _get_string_reduction_arg(
      *, size_average: Optional[bool], reduce: Optional[bool]
  ) -> str:
      if size_average is None:
          size_average = True
      if reduce is None:
          reduce = True
      if size_average and reduce:
          ret = "mean"
      elif reduce:
          ret = "sum"
      else:
          ret = "none"
      return ret
  
imports: import math
  from functools import wraps
  from typing import Callable, Optional, Union
  import torch
  import torch._prims
  import torch._prims_common
  import torch._refs
  from torch._decomp import register_decomposition
  from torch._prims_common import ELEMENTWISE_TYPE_PROMOTION_KIND, NumberType, ShapeType, TensorLike, TensorLikeType
  from torch._prims_common.wrappers import elementwise_type_promotion_wrapper, elementwise_unary_scalar_wrapper, out_wrapper
  from torch._refs import _make_inplace
label_desc: Use image node_id 21 for calling a global function with example usage: _get_string_reduction_arg() and returns: ret