from apollo_utils.core.utils.ext_enum import ExtEnum
from apollo_utils.core.utils.singleton import SingletonMeta


class Absent(metaclass=SingletonMeta):
    pass


class EmptyDict(metaclass=SingletonMeta):
    pass


ABSENT = Absent()  # value to use as None in cases where None is a valid value
EMPTY_DICT = EmptyDict()


class SortOrder(ExtEnum):
    ASC = "asc"
    DESC = "desc"


LAST_WEEK_START_DAYS = 6
PREVIOUS_WEEK_START_DAYS = 13