Change it's to its

src/smart-contracts/concepts/valid-code.md

@@ -2,7 +2,7 @@
 # Valid Code
 
 ## No Classes Allowed!
-Contracting maintains a strict 'no classes' model. This forces you as the developer to create more procedural code that is explicit and completely self-contained. Contracts must be easy to read and understand for validity. Instead of thinking of your code in classes, think of each contract as a 'module' that exposes certain functions to it's users.
+Contracting maintains a strict 'no classes' model. This forces you as the developer to create more procedural code that is explicit and completely self-contained. Contracts must be easy to read and understand for validity. Instead of thinking of your code in classes, think of each contract as a 'module' that exposes certain functions to its users.
 
 All `class` keywords will fail your contract on submission. Even if you try to use classes for object oriented code, you will have to find another way to express your structures.