python3安装sdk成功，但是仍然显示 ImportError: No module named 'aliyunsdkcore'

d:\python\aliyun>python --version
Python 3.5.4

d:\python\aliyun>pip install aliyun-python-sdk-core-v3
Collecting aliyun-python-sdk-core-v3
Installing collected packages: aliyun-python-sdk-core-v3
Successfully installed aliyun-python-sdk-core-v3-2.11.0
You are using pip version 18.0, however version 18.1 is available.
You should consider upgrading via the 'python -m pip install --upgrade pip' command.

d:\python\aliyun>python ossSTS客户端.py
Traceback (most recent call last):
  File "ossSTS客户端.py", line 8, in <module>
    from aliyunsdkcore import client
ImportError: No module named 'aliyunsdkcore'

python代码

# -*- coding: utf-8 -*-

from aliyunsdkcore import client
from aliyunsdksts.request.v20150401 import AssumeRoleRequest
import json
import oss2