code: def add_500mb(self):
      self.data.append(os.urandom(500 * 1024**2))
      self.x += 1
      return self.x
  
file_path: PARL/parl/remote/tests/actor_max_memory_test.py
imports: import os
  import parl
  import unittest
  import time
  from parl.remote.client import get_global_client
  from parl.utils.test_utils import XparlTestCase
label_desc: Use image node_id 2 for calling the Actor obj's underlying member method code with example usage: obj.add_500mb() and returns: self