def index_exists(self, table: str, indexname: str) -> bool:
        """Does an index exist? (Specific to MySQL.)"""
        # MySQL:
        sql = ("SELECT COUNT(*) FROM information_schema.statistics"
               " WHERE table_name=? AND index_name=?")
        row = self.fetchone(sql, table, indexname)
        return True if row[0] >= 1 else False