code: def dist_tversky(src, tar, qval=2, alpha=1, beta=1, bias=None):
      
      return Tversky().dist(src, tar, qval, alpha, beta, bias)
docs: Return the Tversky distance between two strings.
  
      This is a wrapper for :py:meth:`Tversky.dist`.
  
      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
      alpha : float
          Tversky index parameter as described above
      beta : float
          Tversky index parameter as described above
      bias : float
          The symmetric Tversky index bias parameter
  
      Returns
      -------
      float
          Tversky distance
  
      Examples
      --------
      >>> dist_tversky('cat', 'hat')
      0.6666666666666667
      >>> dist_tversky('Niall', 'Neil')
      0.7777777777777778
      >>> dist_tversky('aluminum', 'Catalan')
      0.9375
      >>> dist_tversky('ATCG', 'TAGC')
      1.0