'str' object has no attribute 'get'

在做爬虫实验爬微博评论的时候遇到的情况
这里是部分源码

def getData(url):
    headers = {
        "User-Agent": "",
        "Cookie": ""
    }

    try:
        r = requests.get(url, headers=headers)
        print(r.json())
        return r.json()
    except:
        return "ERROR!!!"

        jsonData = getData(url)
        time.sleep(3)
        num += 1
        if jsonData.get('ok') == 0 :
            break
        else:
            getComments(jsonData, list)

每次运行后都是爬两条评论后就报错，查了很多方法都没解决
File "", line , in
if jsonData.get('ok') == 0 :
AttributeError: 'str' object has no attribute 'get'

User-Agent 和 Cookie都是空的？是的话问题就在这