code: def KentFosterII_calc(TP, FP, FN, TN):
      """
      Calculate Kent & Foster II similarity.
  
      :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: Kent & Foster II similarity as float
      """
      try:
          part1 = ((TN + FP) * (TN + FN)) / (TN + FP + FN)
          return (TN - part1) / (TN - part1 + FP + FN)
      except Exception:
          return "None"
  
imports: from __future__ import division
  from enum import Enum
  import math
label_desc: Use image node_id 53 for calling a global function with example usage: KentFosterII_calc(TP, FP, FN, TN) and returns: unknown, str