code: def test_get_method(self):
      obj = optimizers.get("sgd")
      self.assertIsInstance(obj, optimizers.SGD)
      obj = optimizers.get("adamw")
      self.assertIsInstance(obj, optimizers.AdamW)
  
      obj = optimizers.get(None)
      self.assertEqual(obj, None)
  
      with self.assertRaises(ValueError):
          optimizers.get("typo")
  
file_path: keras/keras/optimizers/optimizer_test.py
imports: import numpy
  import pytest
  from keras import backend
  from keras import constraints
  from keras import layers
  from keras import models
  from keras import optimizers
  from keras import testing
label_desc: Use image node_id 5 for calling the OptimizerTest obj's underlying member method code with example usage: obj.test_get_method() without return types