How to use the deal.ensure function in deal

    @deal.ensure(lambda a, b, result: a > 0 and b > 0 and result != 'same number')
    def func(a, b):
        if a == b:
            return 'same number'
        else:
            return 'different numbers'

        @deal.ensure(lambda a, b, result: a > 0 and b > 0 and result != 'same number')
        def func(a, b):
            if a == b:
                return 'same number'
            else:
                return 'different numbers'

    @deal.ensure(lambda a, b, result: a > 0 and b > 0 and result != 'same number')
    async def func(a, b):
        if a == b:
            return 'same number'
        else:
            return 'different numbers'

    @deal.ensure(lambda *args, **kwargs: True)
    @deal.raises(ValueError)
    @deal.offline()
    @deal.offline
    @deal.safe
    @deal.safe()
    @deal.silent
    @deal.silent()
    @deal.pure
    @deal.chain(deal.safe, deal.silent)
    def func(x: int) -> int:
        """docs were before docker
        """
        return x

    @deal.ensure(lambda x, y, result: result > y ** 2)
    def multiply(x, y):
        yield x * y
        yield x * y * 2
        yield x * y * 4

@deal.ensure(lambda _: _.result.endswith(_.right))
@deal.has()
def concat(left: str, right: str) -> str:
    return left + right