code: def _get_metadir(
      flow_name=None, run_id=None, step_name=None, task_id=None
  ):
      from metaflow.plugins.datastores.local_storage import LocalStorage
  
      root_path = LocalMetadataProvider._make_path(
          flow_name, run_id, step_name, task_id, create_on_absent=False
      )
      if root_path is None:
          return None
      subpath = os.path.join(root_path, LocalStorage.METADATA_DIR)
      if os.path.isdir(subpath):
          return subpath
      return None
  
imports: import collections
  import glob
  import json
  import os
  import random
  import tempfile
  import time
  from collections import namedtuple
  from metaflow.exception import MetaflowInternalError, MetaflowTaggingError
  from metaflow.metadata.metadata import ObjectOrder
  from metaflow.metaflow_config import DATASTORE_LOCAL_DIR
  from metaflow.metadata import MetadataProvider
  from metaflow.tagging_util import MAX_USER_TAG_SET_SIZE, validate_tags
label_desc: Use image node_id 21 for calling the LocalMetadataProvider obj's underlying member method code with example usage: obj._get_metadir(flow_name, run_id, step_name, task_id) and returns: None, None, subpath