docs: def fetch_class(full_class_name):
      """Fetches the given class.
  
      :param string full_class_name: Name of the class to be fetched.
      """
      (module_name, class_name) = full_class_name.rsplit('.', 1)
      module = importlib.import_module(module_name)
      return getattr(module, class_name)