class_docstr: Base class for experiment loggers.
class_docstr_tok: ["Base","class","for","experiment","loggers","."]
docstr: Return the root directory where experiment logs get saved, or `None` if the logger does not save data
  locally.
docstr_tok: ["Return","the","root","directory","where","experiment","logs","get","saved",",","or","`","None","`","if","the","logger","does","not","save","data","locally","."]
code: def save_dir(self) -> Optional[str]:
      """Return the root directory where experiment logs get saved, or `None` if the logger does not save data
      locally."""
      return None
  
imports: import functools
  import operator
  from abc import ABC
  from collections import defaultdict
  from typing import Any, Callable, Dict, Mapping, Optional, Sequence
  import numpy
  from typing_extensions import override
  from lightning.fabric.loggers import Logger
  from lightning.fabric.loggers.logger import _DummyExperiment
  from lightning.fabric.loggers.logger import rank_zero_experiment
  from lightning.pytorch.callbacks.model_checkpoint import ModelCheckpoint
label_desc: Use image node_id 2 for calling the Logger obj's underlying member method code with example usage: obj.save_dir() and returns: None