Eternal storage for uint256

uint256_eternal_storage.sol

mapping(bytes32 => uint256) internal uInt256Storage;

function getUInt256(bytes32 _key) external view returns (uint256) {
  return uInt256Storage[_key];
}

function setUInt256(bytes32 _key, uint256 _value) external {
  uInt256Storage[_key] = _value;
}

function deleteUInt256(bytes32 _key) external {
  delete uInt256Storage[_key];
}