code: def _standardize(x):
      """
      Standardize a vector to be mean 0 and std 1.
      """
      return (np.array(x) - np.mean(x)) / np.std(x)
  
imports: import random
  import numpy
  import pandas
  from sklearn.datasets import make_classification
  from scipy.optimize import fsolve
  from scipy.special import expit
  from scipy.special import logit
label_desc: Use image node_id 8 for calling a global function with example usage: _standardize(x) and returns: unknown