The CLI standard libraries (ISO/IEC 23271) provide a collection of common types that can be used by multiple languages. With the addition of generics to the CLI, the standard libraries have been extended to include a number of common generic types, in particular, collections. However, at present, these libraries do not include many simple generic types found in a number of different languages. Any language which uses these common types must implement them rather than deferring to the CLI library, thereby reducing language inter-operability. ISO/IEC TR 25438:2006 addresses this issue by providing a number of these common types.