在看openstack nova 的代码的时候，看到了这个问题，不知道这个函数代码是什么意思？这个是类作为一个函数的装饰器，是怎么装饰的？

class wsgify(object):

 RequestClass = Request

def __init__(self, func=None, RequestClass=None,
             args=(), kwargs=None, middleware_wraps=None):
    self.func = func
    if (RequestClass is not None
        and RequestClass is not self.RequestClass):
        self.RequestClass = RequestClass
    self.args = tuple(args)
    if kwargs is None:
        kwargs = {}
    self.kwargs = kwargs
    self.middleware_wraps = middleware_wraps
    
    
**@webob.dec.wsgify(RequestClass=wsgi.Request)
def __call__(self, req):**
    if os.path.normpath(req.path_info) == "/":
        resp = base.ec2_md_print(base.VERSIONS + ["latest"])
        req.response.body = resp
        req.response.content_type = base.MIME_TYPE_TEXT_PLAIN
        return req.response

请问下这个装饰器是什么意思啊？