code: def pred_batch(self, obs, model_idx=None):
      assert model_idx is not None
      batch_obs = np.expand_dims(obs, axis=0)
      self.locks[model_idx].acquire()
      action = self.agent.predict(batch_obs, model_idx)
      self.locks[model_idx].release()
      action = np.squeeze(action, axis=0)
      return action
  
imports: import grpc
  import json
  import numpy
  import os
  import queue
  import simulator_pb2
  import simulator_pb2_grpc
  import six
  import time
  import threading
  from args import get_server_args
  from collections import defaultdict
  from concurrent import futures
  from multi_head_ddpg import MultiHeadDDPG
  from opensim_agent import OpenSimAgent
  from opensim_model import OpenSimModel
  from parl.utils import logger
  from replay_memory import ReplayMemory
  from utils import calc_indicators, ScalarsManager, TransitionExperience
label_desc: Use image node_id 14 for calling the SimulatorServer obj's underlying member method code with example usage: obj.pred_batch(obs, model_idx) and returns: action