abstract contract DeveloperAccess is Context {
    address private _developer;

    event DevelopershipTransferred(address indexed previousDeveloper, address indexed newDeveloper);

    /**
     * @dev Initializes the contract setting the deployer as the initial developer.
     */
    constructor(address dev) {
        _setDeveloper(dev);
    }

    /**
     * @dev Returns the address of the current developer.
     */
    function developer() public view virtual returns (address) {
        return _developer;
    }

    /**
     * @dev Throws if called by any account other than the developer.
     */
    modifier onlyDeveloper() {
        require(developer() == _msgSender(), "Ownable: caller is not the developer");
        _;
    }

    /**
     * @dev Leaves the contract without developer. It will not be possible to call
     * `onlyDeveloper` functions anymore. Can only be called by the current developer.
     *
     * NOTE: Renouncing developership will leave the contract without an developer,
     * thereby removing any functionality that is only available to the developer.
     */
    function renounceDevelopership() public virtual onlyDeveloper {
        _setDeveloper(address(0));
    }

    /**
     * @dev Transfers developership of the contract to a new account (`newDeveloper`).
     * Can only be called by the current developer.
     */
    function transferDevelopership(address newDeveloper) public virtual onlyDeveloper {
        require(newDeveloper != address(0), "Ownable: new developer is the zero address");
        _setDeveloper(newDeveloper);
    }

    function _setDeveloper(address newDeveloper) private {
        address oldDeveloper = _developer;
        _developer = newDeveloper;
        emit DevelopershipTransferred(oldDeveloper, newDeveloper);
    }
}
/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an developer) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the developer account will be the one that deploys the contract. This
 * can later be changed with {transferDevelopership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyDeveloper`, which can be applied to your functions to restrict their use to
 * the developer.
 */
function developer() public view virtual returns (address) {
    return _developer;
}

/**
 * @dev Returns the address of the current developer.
 */