```\nfunction changeFees(uint256 newBuyMul, uint256 newSellMul)\n    external\n    onlyOwner\n{\n    require(\n        newBuyMul >= 90 &&\n            newSellMul >= 90 &&\n            newBuyMul <= 100 &&\n            newSellMul <= 100,\n        "Fees are too high"\n    );\n\n    buyMul = newBuyMul;\n    sellMul = newSellMul;\n\n    emit FeesMulChanged(newBuyMul, newSellMul);\n}\n```\n