code: def default(val, d):
      if exists(val):
          return val
      return d() if callable(d) else d
  
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 2 for calling a global function with example usage: default(val, d) and returns: unknown, val