code: def _cur_loss_scaler(self):
      assert 0 <= self._loss_idx < self._num_loss
      return self._loss_scaler[self._loss_idx]
  
file_path: apex/apex/amp/opt.py
imports: import contextlib
  import warnings
  from .scaler import LossScaler, master_params
  from ._amp_state import maybe_print
  import numpy
label_desc: Use image node_id 3 for calling the OptimWrapper obj's underlying member method code with example usage: obj._cur_loss_scaler() and returns: self