macaca + python 获取元素大小报错

size=webelement.size
rect=webelement.rect
都报错如下有：

if http_error_msg:

raise HTTPError(http_error_msg, response=self)
E requests.exceptions.HTTPError: 404 Client Error: Not Found for url: http://localhost:3456/wd/hub/session/c2078c20-c8f1-48d8-84f3-5023e340a653/element/0.9202883099329582-3/size

c:\python36\lib\site-packages\requests\models.py:935: HTTPError