diff --git a/code/celo101-code-chapter_2/2-6-optimising-the-contract/marketplace.sol b/code/celo101-code-chapter_2/2-6-optimising-the-contract/marketplace.sol
index 0d62ff7..3335120 100644
--- a/code/celo101-code-chapter_2/2-6-optimising-the-contract/marketplace.sol
+++ b/code/celo101-code-chapter_2/2-6-optimising-the-contract/marketplace.sol
@@ -24,7 +24,7 @@ contract Marketplace {
         string memory _description, 
         string memory _location, 
         uint _price
-    ) public {
+    ) public external {
         uint _sold = 0;
         products[productsLength] = Product(
             payable(msg.sender),
@@ -61,4 +61,4 @@ contract Marketplace {
     function getProductsLength() public view returns (uint) {
         return (productsLength);
     }
-}
\ No newline at end of file
+}