docstr: Test the lockstep mode by adding batches from multiple policies.
docstr_tok: ["Test","the","lockstep","mode","by","adding","batches","from","multiple","policies","."]
code: def test_lockstep_mode(self):
      """Test the lockstep mode by adding batches from multiple policies."""
      self.batch_id = 0
  
      num_policies = 4
      num_batches = 13
      buffer_size = 15
  
      # Test lockstep mode with different policy ids using MultiAgentBatches
      buffer = MultiAgentPrioritizedReplayBuffer(
          capacity=buffer_size,
          replay_mode="lockstep",
          num_shards=1,
      )
  
      self._add_multi_agent_batch_to_buffer(
          buffer, num_policies=num_policies, num_batches=num_batches
      )
  
      _id, _buffer = next(buffer.replay_buffers.items().__iter__())
      assert _id == _ALL_POLICIES
      assert len(buffer) == num_batches
  
      # Add batches until the buffer is full
      self._add_multi_agent_batch_to_buffer(
          buffer, num_policies=num_policies, num_batches=num_batches
      )
  
      assert _id == _ALL_POLICIES
      assert len(buffer) == buffer_size
  
file_path: ray/python/ray/rllib/utils/replay_buffers/tests/test_multi_agent_prioritized_replay_buffer.py
imports: import unittest
  import numpy
  from ray.rllib.policy.sample_batch import SampleBatch, MultiAgentBatch, DEFAULT_POLICY_ID, concat_samples
  from ray.rllib.utils.replay_buffers.multi_agent_prioritized_replay_buffer import MultiAgentPrioritizedReplayBuffer
  from ray.rllib.utils.test_utils import check
  from ray.rllib.utils.replay_buffers.replay_buffer import _ALL_POLICIES
label_desc: Use image node_id 5 for calling the TestMultiAgentPrioritizedReplayBuffer obj's underlying member method code with example usage: obj.test_lockstep_mode() without return types