code: def IS_calc(TP, FP, FN, POP):
      """
      Calculate Information score (IS).
  
      :param TP: true positive
      :type TP: int
      :param FP: false positive
      :type FP: int
      :param FN: false negative
      :type FN: int
      :param POP: population or total number of samples
      :type POP: int
      :return: IS as float
      """
      try:
          result = -math.log(((TP + FN) / POP), 2) + math.log(
              (TP / (TP + FP)), 2
          )
          return result
      except (ZeroDivisionError, TypeError, ValueError):
          return "None"
  
imports: from __future__ import division
  import math
  from .pycm_util import normal_quantile
  from .pycm_interpret import *
  from .pycm_param import CLASS_PARAMS
label_desc: Use image node_id 23 for calling a global function with example usage: IS_calc(TP, FP, FN, POP) and returns: result, str