错误信息：

File "/usr/lib/python2.7/site-packages/urllib3/util/__init__.py", line 4, in <module>

    from .request import make_headers

  File "/usr/lib/python2.7/site-packages/urllib3/util/request.py", line 5, in <module>

    from ..exceptions import UnrewindableBodyError

ImportError: cannot import name UnrewindableBodyError

解决办法，重装 urllib3 库：

pip uninstall urllib3

pip install urllib3