code: def jaccardIndex(s1, s2, stranded=False):
    
  
    def count(s):
      """ sum the size of regions in s. """
      tot = 0
      for r in s:
        tot += len(r)
      return tot
  
    if stranded:
      raise GenomicIntervalError("Sorry, stranded mode for computing Jaccard " +
                                 "index hasn't been implemented yet.")
  
    s1 = collapseRegions(s1)
    s2 = collapseRegions(s2)
    intersection = regionsIntersection(s1, s2)
    c_i = count(intersection)
    return c_i / float(count(s1) + count(s2) - c_i)
docs: Compute the Jaccard index for two collections of genomic intervals
  
    :param s1: the first set of genomic intervals
    :param s2: the second set of genomic intervals
    :param stranded: if True, treat regions on different strands as not
                     intersecting each other, even if they occupy the same
                     genomic region.
    :return: Jaccard index