1  pragma solidity ^0.5.2;
 2  
 3  
 4  contract Controlled {
 5      /// @notice The address of the controller is the only address that can call
 6      ///  a function with this modifier
 7      modifier onlyController { 
 8          require(msg.sender == controller, "Unauthorized"); 
 9          _; 
10      }
11  
12      address payable public controller;
13  
14      constructor() internal { 
15          controller = msg.sender; 
16      }
17  
18      /// @notice Changes the controller of the contract
19      /// @param _newController The new controller of the contract
20      function changeController(address payable _newController) external onlyController {
21          controller = _newController;
22      }
23  }