docs: def _get_hit(self, key):
          """Try to do a value lookup from the existing cache entries."""
          try:
              result = self.cache[key]
              self.hits += 1
              self._ref_key(key)
              return result
          except KeyError:
              pass
  
          result = self.weakrefs[key]
          self.refhits += 1
          self.cache[key] = result
          self._ref_key(key)
          return result