code: def overall_jaccard_index_calc(jaccard_list):
      """
      Calculate Overall Jaccard index.
  
      :param jaccard_list: list of Jaccard index for each class
      :type jaccard_list: list
      :return: (Jaccard_sum, Jaccard_mean) as tuple
      """
      try:
          jaccard_sum = sum(jaccard_list)
          jaccard_mean = jaccard_sum / len(jaccard_list)
          return (jaccard_sum, jaccard_mean)
      except Exception:
          return "None"
  
imports: from __future__ import division
  import math
  import operator
  from functools import reduce
  from .pycm_interpret import *
  from .pycm_ci import kappa_SE_calc, CI_calc, SE_calc
  from .pycm_util import complement
label_desc: Use image node_id 40 for calling a global function with example usage: overall_jaccard_index_calc(jaccard_list) and returns: jaccard_sum,  jaccard_mean, str