code: def sim(self, src, tar, qval=2):
          r
          return super(self.__class__, self).sim(src, tar, qval, 1, 1)
docs: r"""Return the Jaccard similarity of two strings.
  
          Parameters
          ----------
          src : str
              Source string (or QGrams/Counter objects) for comparison
          tar : str
              Target string (or QGrams/Counter objects) for comparison
          qval : int
              The length of each q-gram; 0 for non-q-gram version
  
          Returns
          -------
          float
              Jaccard similarity
  
          Examples
          --------
          >>> cmp = Jaccard()
          >>> cmp.sim('cat', 'hat')
          0.3333333333333333
          >>> cmp.sim('Niall', 'Neil')
          0.2222222222222222
          >>> cmp.sim('aluminum', 'Catalan')
          0.0625
          >>> cmp.sim('ATCG', 'TAGC')
          0.0