function approve(address spender, uint256 value) public returns (bool);
  event Approval(
    address indexed owner,
    address indexed spender,
    uint256 value
  );
}


contract IModuleFactory is Ownable {

    ERC20 public polyToken;
    uint256 public setupCost;
    uint256 public usageCost;
    uint256 public monthlySubscriptionCost;

    event LogChangeFactorySetupFee(uint256 _oldSetupcost, uint256 _newSetupCost, address _moduleFactory);
    event LogChangeFactoryUsageFee(uint256 _oldUsageCost, uint256 _newUsageCost, address _moduleFactory);
    event LogChangeFactorySubscriptionFee(uint256 _oldSubscriptionCost, uint256 _newMonthlySubscriptionCost, address _moduleFactory);
    event LogGenerateModuleFromFactory(address _module, bytes32 indexed _moduleName, address indexed _moduleFactory, address _creator, uint256 _timestamp);

    
    constructor (address _polyAddress, uint256 _setupCost, uint256 _usageCost, uint256 _subscriptionCost) public {
      polyToken = ERC20(_polyAddress);
      setupCost = _setupCost;
      usageCost = _usageCost;
      monthlySubscriptionCost = _subscriptionCost;
    }