code: def activation(activation_fun=None):
      """Helper for building an activation layer."""
      activation_fun = (
          activation_fun or cfg.MODEL.ACTIVATION_FUN
      ).lower()
      if activation_fun == "relu":
          return nn.ReLU(inplace=cfg.MODEL.ACTIVATION_INPLACE)
      elif activation_fun == "silu" or activation_fun == "swish":
          try:
              return torch.nn.SiLU()
          except AttributeError:
              return SiLU()
      elif activation_fun == "gelu":
          return torch.nn.GELU()
      else:
          raise AssertionError(
              "Unknown MODEL.ACTIVATION_FUN: " + activation_fun
          )
  
imports: import numpy
  import torch
  import torch.nn
  from pycls.core.config import cfg
  from torch.nn import Module
label_desc: Use image node_id 8 for calling a global function with example usage: activation(activation_fun) and returns: nn, torch, torch, SiLU