MyToken.sol with multlple agents

MyToken.sol

pragma solidity ^0.4.23;

import "./Ownable.sol";

contract MyToken is Ownable {
    mapping (address => bool) public agents;

    modifier onlyAgent {
      require(agents[msg.sender]);
      _;
    }

    setAgent(address _agent, bool _enabled) public onlyOwner {
        agents[_agent] = _enabled;
    }
}