code: def tanhshrink(a: TensorLikeType) -> TensorLikeType:
      """
      Reference implementation of torch.nn.functional.tanhshrink
      """
      if not isinstance(a, TensorLike):
          raise RuntimeError(
              "Expected a tensor input for an elementwise unary operation!"
          )
      return a - torch.tanh(a)
  
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 31 for calling a global function with example usage: tanhshrink(a) and returns: unknown