interface Nest_NToken {
    // Additional issuance
    function increaseTotal(uint256 value) external;
    // Check mining information
    function checkBlockInfo() external view returns(uint256 createBlock, uint256 recentlyUsedBlock);
    // Check creator
    function checkBidder() external view returns(address);
    function totalSupply() external view returns (uint256);
    function balanceOf(address account) external view returns (uint256);
    function transfer(address recipient, uint256 amount) external returns (bool);
    function allowance(address owner, address spender) external view returns (uint256);
    function approve(address spender, uint256 amount) external returns (bool);
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);
}
// NToken contract
function checkBidder() external view returns(address);

// Check creator