code: def _get_optimizer(self):
      return Optimizer.from_params(
          model_parameters=self.model.named_parameters(),
          params=Params(
              {"type": "sgd", "lr": 1.0, "momentum": self.base_momentum}
          ),
      )
  
file_path: allennlp/tests/training/momentum_schedulers/inverted_triangular_test.py
imports: from math import isclose
  import torch
  from allennlp.common.params import Params
  from allennlp.common.testing import AllenNlpTestCase
  from allennlp.training.momentum_schedulers import MomentumScheduler
  from allennlp.training.optimizers import Optimizer
label_desc: Use image node_id 2 for calling the InvertedTriangularTest obj's underlying member method code with example usage: obj._get_optimizer() and returns: Optimizer