function payStakingFee(address payer, uint256 value, uint80 numerator, uint80 denominator, uint256 flatRate, address otherParticipant) private returns (uint256) {
        if (noFeesList.onList(payer) || noFeesList.onList(otherParticipant)) {
            return 0;
        }
        uint256 stakingFee = value.mul(numerator).div(denominator).add(flatRate);
        if (stakingFee > 0) {
            transferFromWithoutAllowance(payer, staker, stakingFee);
        }
        return stakingFee;
    }