docs: def required_data(*data):
      """
      Task decorator which checks if the given variables (indices) are stored
      inside the task data.
      """
  
      def decorator_fn(f):
  
          @wraps(f)
          def required_data_decorator(*args, **kwargs):
              task_data = _get_data_from_args(args).get_data()
              for i in data:
                  if i not in task_data:
                      raise KeyError(
                          'Missing required parameter "{0}" for task.'.format(i))
  
              return f(*args, **kwargs)
  
          return required_data_decorator
  
      return decorator_fn