code: def exists(val):
      return val is not None
  
file_path: mixture-of-attention/mixture_of_attention/attend.py
imports: from collections import namedtuple
  from functools import wraps
  from packaging import version
  import torch
  from torch import nn, einsum
  import torch.nn.functional
  from einops import rearrange
label_desc: Use image node_id 1 for calling a global function with example usage: exists(val) and returns: unknown