code: def values_to_labels(fg_vals, bg_vals):
       
      y_true = np.hstack((np.ones(len(fg_vals)), np.zeros(len(bg_vals))))
      y_score = np.hstack((fg_vals, bg_vals))
      
      return y_true, y_score
docs: Convert two arrays of values to an array of labels and an array of scores.
  
      Parameters
      ----------
      fg_vals : array_like
          The list of values for the positive set.
  
      bg_vals : array_like
          The list of values for the negative set.
  
      Returns
      -------
      y_true : array
          Labels.
      y_score : array
          Values.