def get_synset_by_id(self, mongo_id):
cache_hit = None<EOL>if self._synset_cache is not None:<EOL><INDENT>cache_hit = self._synset_cache.get(mongo_id)<EOL><DEDENT>if cache_hit is not None:<EOL><INDENT>return cache_hit<EOL><DEDENT>synset_dict = self._mongo_db.synsets.find_one({'<STR_LIT>': mongo_id})<EOL>if synset_dict is not None:<EOL><INDENT>synset = Synset(self, synset_dict)<EOL>if self._synset_cache is not None:<EOL><INDENT>self._synset_cache.put(mongo_id, synset)<EOL><DEDENT>return synset<EOL><DEDENT>
Builds a Synset object from the database entry with the given
ObjectId.

Arguments:
- `mongo_id`: a bson.objectid.ObjectId object