code: def get_metadata(self):
      return self.metadata
  
imports: import argparse
  import json
  import logging
  import numpy
  import os
  import threading
  import time
  from ray._private.test_utils import monitor_memory_usage
  from ray.data._internal.progress_bar import ProgressBar
  from collections import namedtuple
  from queue import Queue
  import ray
label_desc: Use image node_id 5 for calling the PiCalculator obj's underlying member method code with example usage: obj.get_metadata() and returns: self