code: def zero_grad(self, params=None):
      if params is None:
          for param in self.params:
              if param.requires_grad and param.grad is not None:
                  param.grad.zero_()
      else:
          for param in params:
              if param.requires_grad and param.grad is not None:
                  param.grad.zero_()
  
file_path: PARL/benchmark/torch/maml++/maml_model.py
imports: import torch
  import torch.nn
  import torch.nn.functional
  import parl
label_desc: Use image node_id 3 for calling the MAMLModel obj's underlying member method code with example usage: obj.zero_grad(params) without return types