code: def sInd_calc(dInd):
      """
      Calculate Similarity index (sInd).
  
      :param dInd: dInd
      :type dInd: float
      :return: sInd as float
      """
      try:
          return 1 - (dInd / (math.sqrt(2)))
      except (ZeroDivisionError, 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 28 for calling a global function with example usage: sInd_calc(dInd) and returns: unknown, str