How to do an action in a contract to transfer tokens to other user accounts without adding permission? Actually, in dawn3.0 i can use the function like this below, but in dawn 4.0 it doesn't work

        action(
            permission_level{ lender, N(active) },
            N(eosio.eos), N(transfer),
            std::make_tuple(lender, _self, shouldback,std::string(""))
        ).send();