code: def UCB(mean, std, beta):
      return mean + beta * std
  
file_path: modAL/modAL/acquisition.py
imports: import numpy
  from scipy.special import ndtr
  from scipy.stats import norm
  from sklearn.exceptions import NotFittedError
  from modAL.models.base import BaseLearner
  from modAL.utils.data import modALinput
  from modAL.utils.selection import multi_argmax
label_desc: Use image node_id 3 for calling a global function with example usage: UCB(mean, std, beta) and returns: unknown