code: def text_ratio(self):
          
          return _calculate_ratio(
              self.match_length(),
              self._text_length(self.a) + self._text_length(self.b),
          )
docs: Return a measure of the sequences' word similarity (float in [0,1]).
  
          Each word has weight equal to its length for this measure
  
          >>> m = WordMatcher(a=['abcdef', '12'], b=['abcdef', '34']) # 3/4 of the text is the same
          >>> '%.3f' % m.ratio() # normal ratio fails
          '0.500'
          >>> '%.3f' % m.text_ratio() # text ratio is accurate
          '0.750'