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Note: this function uses a\n     * `revert` opcode (which leaves remaining gas untouched) while Solidity\n     * uses an invalid opcode to revert (consuming all remaining gas).\n     *\n     * Requirements:\n     *\n     * - The divisor cannot be zero.\n     */\n    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {\n        require(b > 0, errorMessage);\n        uint256 c = a / b;\n        // assert(a == b * c + a % b); // There is no case in which this doesn't hold\n\n        return c;\n    }\n\n    /**\n     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),\n     * Reverts when dividing by zero.\n     *\n     * Counterpart to Solidity's `%` operator. 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