code: def maybe(fn):
      @wraps(fn)
      def inner(x):
          if not exists(x):
              return x
          return fn(x)
  
      return inner
  
imports: import math
  from functools import partial, wraps
  import torch
  import torch.nn
  from einops import repeat
  from torch.special import expm1
  from nemo.collections.multimodal.parts.utils import randn_like
label_desc: Use image node_id 3 for calling a global function with example usage: maybe(fn) and returns: inner, fn, x