code: def add_param_group(self, param_group):
      return self._optimizer.add_param_group(param_group)
  
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 12 for calling the OptimWrapper obj's underlying member method code with example usage: obj.add_param_group(param_group) and returns: self