error: command ‘x86_64-linux-gnu-gcc’ failed with exit status 1
解決辦法：sudo apt-get install build-essential libssl-dev libffi-dev python-dev
untimeError: cryptography requires setuptools 18.5 or newer, please upgrade to a newer version of s
解決辦法：setuptool 太老了，更新下: pip install --upgrade setuptools
ImportError: No module named enum
解決辦法：pip install enum34