def METHOD_NAME(self, conf: ConfigTree) -> None:
    conf = conf.with_fallback(DruidMetadataExtractor.DEFAULT_CONFIG)
    self._cluster = conf.get_string(DruidMetadataExtractor.CLUSTER_KEY)
    self.sql_stmt = DruidMetadataExtractor.SQL_STATEMENT.format(
        where_clause_suffix=conf.get_string(DruidMetadataExtractor.WHERE_CLAUSE_SUFFIX_KEY,
                                            default=''))
    self._alchemy_extractor = sql_alchemy_extractor.from_surrounding_config(conf, self.sql_stmt)
    self._extract_iter: Union[None, Iterator] = None