code: def exists(path):
      """
  
      Check if a path exists or not. It supports local, hdfs, s3 file systems.
  
      :param path: file or directory path string.
      :return: if path exists or not.
      """
      if path.startswith("s3"):  # s3://bucket/file_path
          access_key_id = os.environ["AWS_ACCESS_KEY_ID"]
          secret_access_key = os.environ["AWS_SECRET_ACCESS_KEY"]
          import boto3
  
          s3_client = boto3.Session(
              aws_access_key_id=access_key_id,
              aws_secret_access_key=secret_access_key,
          ).client("s3", verify=False)
          path_parts = path.split("://")[1].split("/")
          bucket = path_parts.pop(0)
          key = "/".join(path_parts)
          try:
              s3_client.get_object(Bucket=bucket, Key=key)
          except Exception as ex:
              if ex.response["Error"]["Code"] == "NoSuchKey":
                  return False
              raise ex
          return True
      elif path.startswith("hdfs://"):
          return callZooFunc("float", "exists", path)
      else:
          if path.startswith("file://"):
              path = path[len("file://") :]
          return os.path.exists(path)
  
file_path: analytics-zoo/pyzoo/zoo/orca/data/file.py
imports: import os
  from zoo.common.utils import callZooFunc
label_desc: Use image node_id 4 for calling a global function with example usage: exists(path) and returns: True, callZooFunc, os, False