code: def test_train_and_eval_mode(self):
      model = TestModel()
      alg = TestAlgorithm(model)
      agent = TestAgent(alg)
      obs = np.random.random([1, 4]).astype("float32")
      agent.train()
      self.assertTrue(agent.training)
      train_mode_output = agent.predict(obs)
      agent.eval()
      self.assertFalse(agent.training)
      eval_mode_output = agent.predict(obs)
      self.assertEqual(train_mode_output, eval_mode_output)
  
imports: import numpy
  import unittest
  import paddle
  import paddle.nn
  import parl
  import os
label_desc: Use image node_id 15 for calling the AgentBaseTest obj's underlying member method code with example usage: obj.test_train_and_eval_mode() without return types