code: def dist(self, src, tar, max_offset=5, max_distance=0):
          
          return self.dist_abs(src, tar, max_offset, max_distance) / (
              max(len(src), len(tar), 1)
          )
docs: Return the normalized "common" Sift4 distance between two terms.
  
          This is Sift4 distance, normalized to [0, 1].
  
          Parameters
          ----------
          src : str
              Source string for comparison
          tar : str
              Target string for comparison
          max_offset : int
              The number of characters to search for matching letters
          max_distance : int
              The distance at which to stop and exit
  
          Returns
          -------
          float
              The normalized Sift4 distance
  
          Examples
          --------
          >>> cmp = Sift4()
          >>> round(cmp.dist('cat', 'hat'), 12)
          0.333333333333
          >>> cmp.dist('Niall', 'Neil')
          0.4
          >>> cmp.dist('Colin', 'Cuilen')
          0.5
          >>> cmp.dist('ATCG', 'TAGC')
          0.5