docstr: Initializes an APPO instance.
docstr_tok: ["Initializes","an","APPO","instance","."]
code: def __init__(self, config, *args, **kwargs):
      """Initializes an APPO instance."""
      super().__init__(config, *args, **kwargs)
  
      # After init: Initialize target net.
  
      # TODO(avnishn):
      # does this need to happen in __init__? I think we can move it to setup()
      if not self.config._enable_new_api_stack:
          self.workers.local_worker().foreach_policy_to_train(
              lambda p, _: p.update_target()
          )
  
imports: from typing import Optional, Type
  import logging
  from ray.rllib.algorithms.algorithm_config import AlgorithmConfig, NotProvided
  from ray.rllib.algorithms.impala.impala import Impala, ImpalaConfig
  from ray.rllib.core.rl_module.rl_module import SingleAgentRLModuleSpec
  from ray.rllib.policy.policy import Policy
  from ray.rllib.utils.annotations import override
  from ray.rllib.utils.metrics import LAST_TARGET_UPDATE_TS, NUM_AGENT_STEPS_SAMPLED, NUM_ENV_STEPS_SAMPLED, NUM_TARGET_UPDATES
  from ray.rllib.utils.metrics import ALL_MODULES, LEARNER_STATS_KEY
  from ray.rllib.utils.typing import ResultDict
label_desc: Use image node_id 1 to create a new APPO object from inherited base classes: Impala with example: obj = APPO(config)