code: def get_mu_changes(num_arms):
      return torch.tensor([-ARM_MU_DECREASE] * num_arms)
  
imports: import random
  import gym
  import numpy
  import reagent.core.types
  import torch
  from reagent.core.dataclasses import dataclass
  from reagent.core.parameters import NormalizationData, NormalizationKey
  from reagent.gym.envs.env_wrapper import EnvWrapper
  from reagent.gym.normalizers import only_continuous_normalizer
label_desc: Use image node_id 2 for calling a global function with example usage: get_mu_changes(num_arms) and returns: torch