diff --git a/lesson-6/chapter-9/zombiehelper.sol b/lesson-6/chapter-9/zombiehelper.sol
index 2cda9ec..8313075 100644
--- a/lesson-6/chapter-9/zombiehelper.sol
+++ b/lesson-6/chapter-9/zombiehelper.sol
@@ -12,7 +12,7 @@ contract ZombieHelper is ZombieFeeding {
   }
 
   function withdraw() external onlyOwner {
-    address _owner = owner();
+    address payable _owner = address(uint(owner()));
     _owner.transfer(address(this).balance);
   }