import abc
from typing import Tuple, Any

TIMEOUT = 60

class DBAccessor(metaclass=abc.ABCMeta):
    @abc.abstractmethod
    def get_default_db(self, db_name: str):
        pass

    @abc.abstractmethod
    def get_all_dbs(self, default_db: str):
        pass

    @abc.abstractmethod
    def get_schema(self, db: str):
        pass

    @abc.abstractmethod
    def exec_on_db(self, db: str, query: str) -> Tuple[str, Any]:
        pass