code: def _act_fn(
      act_alias: Literal["hswish", "swish", "relu"]
  ) -> Type[nn.Module]:
      if act_alias == "hswish":
          return nn.Hardswish
      elif act_alias == "swish":
          return nn.SiLU
      elif act_alias == "relu":
          return nn.ReLU
      else:
          raise ValueError(f"Unsupported act alias: {act_alias}")
  
imports: from functools import partial
  from typing import Tuple, Optional, Callable, Union, List, Type, cast
  from typing_extensions import Literal
  import torch
  from torch import nn
  import nni
  from nni.nas.nn.pytorch import ModelSpace, Repeat, LayerChoice, MutableLinear, MutableConv2d
  from .proxylessnas import ConvBNReLU, InvertedResidual, DepthwiseSeparableConv, MaybeIntChoice, make_divisible, reset_parameters
  from .utils.pretrained import load_pretrained_weight
label_desc: Use image node_id 2 for calling a global function with example usage: _act_fn(act_alias) and returns: nn, nn, nn