> For the complete documentation index, see [llms.txt](https://darwin-framework.gitbook.io/dogs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://darwin-framework.gitbook.io/dogs/concepts/copyables.md).

# Copyables

The Copyable converter mixin adds the copy mechanism to its type argument. The copy mechanism can be used to create altered version of a source class by specifying patches/overrides in a string-keyed map. This functionality exists to make working with immutable data classes easier and was in earlier version used for merging builder changes onto a object instance.