class_docstr: Stores artifacts as files in a remote directory, via sftp.
code: def _is_directory(self, artifact_path):
      artifact_dir = self.path
      path = (
          posixpath.join(artifact_dir, artifact_path)
          if artifact_path
          else artifact_dir
      )
      with self.pool.get_sfp_connection() as sftp:
          return sftp.isdir(path)
  
imports: import os
  import posixpath
  import sys
  import threading
  import urllib.parse
  from contextlib import contextmanager
  from mlflow.entities import FileInfo
  from mlflow.store.artifact.artifact_repo import ArtifactRepository
label_desc: Use image node_id 4 for calling the SFTPArtifactRepository obj's underlying member method code with example usage: obj._is_directory(artifact_path) and returns: sftp