code: def jaccard_similarity(aset:AssociationSet, s1:str, s2:str) -> float:
      
      a1 = aset.inferred_types(s1)
      a2 = aset.inferred_types(s2)
      num_union = len(a1.union(a2))
      if num_union == 0:
          return 0.0
      return len(a1.intersection(a2)) / num_union
docs: Calculate jaccard index of inferred associations of two subjects
  
      |ancs(s1) /\ ancs(s2)|
      ---
      |ancs(s1) \/ ancs(s2)|