code: def MK_BM_calc(item1, item2):
      """
      Calculate Informedness (BM), Markedness (MK), and Individual classification success index (ICSI).
  
      :param item1: item1 in expression
      :type item1:float
      :param item2: item2 in expression
      :type item2:float
      :return: MK and BM as float
      """
      try:
          result = item1 + item2 - 1
          return result
      except TypeError:
          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 15 for calling a global function with example usage: MK_BM_calc(item1, item2) and returns: result, str