code: def pw_score_jaccard(self, s1 : ClassId, s2 : ClassId) -> SimScore:
          
          am = self.assocmodel
          a1 = am.inferred_types(s1)
          a2 = am.inferred_types(s2)
          num_union = len(a1 | a2)
          if num_union == 0:
              return 0.0
          return len(a1 & a2) / num_union
docs: Calculate jaccard index of inferred associations of two subjects
  
          |ancs(s1) /\ ancs(s2)|
          ---
          |ancs(s1) \/ ancs(s2)|