code: def get_synset_by_id(self, mongo_id):
          '''
          Builds a Synset object from the database entry with the given
          ObjectId.
  
          Arguments:
          - `mongo_id`: a bson.objectid.ObjectId object
          '''
          cache_hit = None
          if self._synset_cache is not None:
              cache_hit = self._synset_cache.get(mongo_id)
          if cache_hit is not None:
              return cache_hit
          synset_dict = self._mongo_db.synsets.find_one({'_id': mongo_id})
          if synset_dict is not None:
              synset = Synset(self, synset_dict)
              if self._synset_cache is not None:
                  self._synset_cache.put(mongo_id, synset)
              return synsef get_synset_by_id(self, mongo_id):
          '''
          Builds a Synset object from the database entry with the given
          ObjectId.
  
          Arguments:
          - `mongo_id`: a bson.objectid.ObjectId object
          '''
          cache_hit = None
          if self._synset_cache is not None:
              cache_hit = self._synset_cache.get(mongo_id)
          if cache_hit is not None:
              return cache_hit
          synset_dict = self._mongo_db.synsets.find_one({'_id': mongo_id})
          if synset_dict is not None:
              synset = Synset(self, synset_dict)
              if self._synset_cache is not None:
                  self._synset_cache.put(mongo_id, synset)
              return synset
docs: Builds a Synset object from the database entry with the given
          ObjectId.
  
          Arguments:
          - `mongo_id`: a bson.objectid.ObjectId object