code: def update_core_cpu(self, param):
      grad = param.grad
      if grad is None:
          return
      hp = self.hyperparam
      ms = self.state["ms"]
  
      ms *= hp.alpha
      ms += (1 - hp.alpha) * grad * grad
      param.array -= hp.lr * grad / numpy.sqrt(ms + hp.eps)
  
file_path: chainerrl/chainerrl/optimizers/rmsprop_async.py
imports: from chainer import cuda
  from chainer import optimizer
  import numpy
label_desc: Use image node_id 3 for calling the RMSpropAsyncRule obj's underlying member method code with example usage: obj.update_core_cpu(param) without return types