class BaseConstraint:
    pass


class AutoNum(BaseConstraint):
    pass


class PrimaryKey(BaseConstraint):
    pass


class NeverEmpty(BaseConstraint):
    pass


class CheckIf(BaseConstraint):
    pass

class BaseConstraint:
    pass


class AutoNum(BaseConstraint):
    pass


class PrimaryKey(BaseConstraint):
    pass


class NeverEmpty(BaseConstraint):
    pass


class CheckIf(BaseConstraint):
    pass
