code: def get_activation(fn: Union[Callable, str]):
      """Get a PyTorch activation function, specified either directly or as a string.
  
      This function simplifies allowing users to specify activation functions by name.
      If a function is provided, it is simply returned unchanged.  If a string is provided,
      the corresponding function in torch.nn.functional is returned.
      """
      if isinstance(fn, str):
          return getattr(torch.nn.functional, fn)
      return fn
  
file_path: deepchem/deepchem/utils/pytorch_utils.py
imports: import scipy
  import torch
  from typing import Callable, Union, List, Generator, Tuple
label_desc: Use image node_id 1 for calling a global function with example usage: get_activation(fn) and returns: fn, getattr