code: def _match(self, local: Tuple[Trigram, ...], other: Trigram) -> float:
          
  
          pos = local[0] % other
          neg = max((x % other for x in local[1:]), default=0)
  
          if neg > pos:
              return 0.0
  
          return pos
docs: Match a trigram with another one. If the negative matching wins,
          returns an inverted matching.