class_docstr: A basic helper class to handle all-reduce operations of gradients across different parallel groups
  before optimization.
  
  Args:
      model (Module): Model where the gradients accumulate.
      optimizer (Optimizer): Optimizer for updating the parameters.
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docstr: A method to accumulate gradients across different parallel groups. Users should
  write their own functions or just use the functions in pre-defined subclasses.
docstr_tok: ["A","method","to","accumulate","gradients","across","different","parallel","groups",".","Users","should","write","their","own","functions","or","just","use","the","functions","in","pre-defined","subclasses","."]
code: def handle_gradient(self):
      """A method to accumulate gradients across different parallel groups. Users should
      write their own functions or just use the functions in pre-defined subclasses.
      """
  
imports: from abc import ABC, abstractmethod
label_desc: Use image node_id 2 for calling the BaseGradientHandler obj's underlying member method code with example usage: obj.handle_gradient() without return types