ImportError: cannot import name UnrewindableBodyError

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