code: def ForbesII_calc(TP, FP, FN, TN):
      """
      Calculate Forbes II correlation.
  
      :param TP: true positive
      :type TP: int
      :param TN: true negative
      :type TN: int
      :param FP: false positive
      :type FP: int
      :param FN: false negative
      :type FN: int
      :return: Forbes II correlation as float
      """
      try:
          n = TP + FP + FN + TN
          part1 = (FP * FN) - (TP * TN)
          part2 = (TP + FP) * (TP + FN)
          part3 = min((TP + FP), (TP + FN))
          return part1 / (part2 - (n * part3))
      except Exception:
          return "None"
  
imports: from __future__ import division
  from enum import Enum
  import math
label_desc: Use image node_id 40 for calling a global function with example usage: ForbesII_calc(TP, FP, FN, TN) and returns: unknown, str