code: def __l2_loss_norm(self, model_weights):
      loss_norm = (
          0.5
          * self.alpha
          * torch.matmul(model_weights.T, model_weights)
      )
      return loss_norm
  
imports: import logging
  import numpy
  import torch
label_desc: Use image node_id 13 for calling the Optimizer obj's underlying member method code with example usage: obj.__l2_loss_norm(model_weights) and returns: loss_norm