The CLS is a set of 41 rules that define the baseline for language interoperability; they are formalized in the Common Language Infrastructure (CLI) specification. CLS compliance is achieved by writing code that adheres to the rules and conventions of the CLS. However, an important point to remember is that only elements that are accessible or visible outside the defining assembly need to be CLS-compliant; this includes elements such as public classes and interfaces as well as public and protected members. Private code elements, which aren’t visible outside the defining assembly, can use any language features without affecting the CLS compliance of the component.