human
I wrote the below code

    @wraps(func)
    def decorated(*args, **kwargs):
        if (not hasattr(decorated, 'return_value')):
            decorated.return_value = func(*args, **kwargs)
        return decorated.return_value
    decorated = _wrap_as_new(func, decorated)
    return serial(decorated)

What's a good function header?
 ... Here's a good function header?
assistant
#Here's a good function header.

def runs_once(func):