code: def act(self, arm_id: str) -> float:
      pass
  
imports: from abc import ABC, abstractmethod
  from functools import partial
  from multiprocessing import Pool
  from typing import Dict, List, Optional, Tuple, Type, Union
  import numpy
  import torch
  from reagent.mab.mab_algorithm import MABAlgo
  from torch import Tensor
label_desc: Use image node_id 2 for calling the MAB obj's underlying member method code with example usage: obj.act(arm_id) without return types