code: def register(cls, origin_type):
          
          def decorator(tracked_type):
              """Adds the decorated class to the `_type_mapping` dictionary."""
              cls._type_mapping[origin_type] = tracked_type
              return tracked_type
          return decorator
docs: Decorator for mutation tracker registration.
  
          The provided `origin_type` is mapped to the decorated class such that
          future calls to `convert()` will convert the object of `origin_type`
          to an instance of the decorated class.