code: def check_backward_validity(inputs):
      if not any(inp.requires_grad for inp in inputs):
          warnings.warn(
              "None of the inputs have requires_grad=True. Gradients will be None"
          )
  
file_path: lavis/lavis/models/timesformer/helpers.py
imports: import logging, warnings
  import os
  import math
  from collections import OrderedDict
  import torch
  import torch.utils.model_zoo
  import torch.nn.functional
label_desc: Use image node_id 9 for calling a global function with example usage: check_backward_validity(inputs) without return types