```\nconstructor(address \_collateral, uint256 decimals) public {\n    require(decimals <= MAX\_DECIMALS, "decimals out of range");\n    require(\_collateral != address(0x0) || (\_collateral == address(0x0) && decimals == 18), "invalid decimals");\n\n    collateral = \_collateral;\n    scaler = (decimals == MAX\_DECIMALS ? 1 : 10\*\*(MAX\_DECIMALS - decimals)).toInt256();\n}\n```\n