based on the objective, instead of minimizing (default: False)
  * **differentiable** (*bool**, **optional*) -- whether autograd
    should occur through the optimizer step in training.
    Otherwise, the step() function runs in a torch.no_grad()
    context. Setting to True can impair performance, so leave it
    False if you don't intend to run autograd through this
    instance (default: False)

add_param_group(param_group)
  Add a param group to the "Optimizer" s *param_groups*.

  This can be useful when fine tuning a pre-trained network as
  frozen layers can be made trainable and added to the "Optimizer"
  as training progresses.

  Parameters:
     **param_group** (*dict*) -- Specifies what Tensors should be
     optimized along with group specific optimization options.

load_state_dict(state_dict)
  Loads the optimizer state.

  Parameters:
     **state_dict** (*dict*) -- optimizer state. Should be an
