class_docstr: Coordinator of n (possibly remote) Learner workers.
  
  Each Learner worker has a copy of the RLModule, the loss function(s), and
  one or more optimizers.
docstr: Checks that the provided checkpoint path is a dir and makes it absolute.
docstr_tok: ["Checks","that","the","provided","checkpoint","path","is","a","dir","and","makes","it","absolute","."]
code: def _resolve_checkpoint_path(path: str) -> pathlib.Path:
      """Checks that the provided checkpoint path is a dir and makes it absolute."""
      path = pathlib.Path(path)
      if not path.is_dir():
          raise ValueError(
              f"Path {path} is not a directory. "
              "Please specify a directory containing the checkpoint files."
          )
      if not path.exists():
          raise ValueError(f"Path {path} does not exist.")
      path = path.absolute()
      return path
  
imports: from collections import defaultdict, Counter
  from functools import partial
  import pathlib
  from typing import Any, Callable, Dict, List, Optional, Set, Type, Union
  import uuid
  import ray
  from ray.rllib.algorithms.algorithm_config import AlgorithmConfig
  from ray.rllib.core.learner.learner import Learner
  from ray.rllib.core.learner.reduce_result_dict_fn import _reduce_mean_results
  from ray.rllib.core.rl_module.rl_module import SingleAgentRLModuleSpec, RLMODULE_STATE_DIR_NAME
  from ray.rllib.policy.sample_batch import MultiAgentBatch
  from ray.rllib.utils.actor_manager import FaultTolerantActorManager
  from ray.rllib.utils.deprecation import Deprecated, deprecation_warning
  from ray.rllib.utils.minibatch_utils import ShardBatchIterator, ShardEpisodesIterator
  from ray.rllib.utils.numpy import convert_to_numpy
  from ray.rllib.utils.typing import EpisodeType, ModuleID, ResultDict, RLModuleSpec, ShouldModuleBeUpdatedFn
  from ray.train._internal.backend_executor import BackendExecutor
  from ray.tune.utils.file_transfer import sync_dir_between_nodes
  from ray.util.annotations import PublicAPI
label_desc: Use image node_id 23 for calling the LearnerGroup obj's underlying member method code with example usage: obj._resolve_checkpoint_path(path) and returns: path