python3: the ssl module in Pytho

使用pip命令出现了问题，提示说找不到ssl模块，出现错误如下：

 pip is configured with locations that require TLS/SSL, however the ssl module in 
 Python is not available.
 Could not fetch URL https:*******: There was a problem confirming the ssl certificate: 
 Can't connect to HTTPS URL because the SSL module is not available. - skipping

解决方法：

1. 第一步：首先确定你已经安装过OpenSSL，没有安装过可以使用以下指令安装

brew install OpenSSL

2. 第二步link你的openssl，链接的过程终端可能有如下打印，详情请看下图

brew unlink openssl && brew link openssl --force

If you need to have openssl first in your PATH run:
  echo 'export PATH="/usr/local/opt/openssl/bin:$PATH"' >> ~/.bash_profile
For compilers to find openssl you may need to set:
  export LDFLAGS="-L/usr/local/opt/openssl/lib"
  export CPPFLAGS="-I/usr/local/opt/openssl/include"

在终端上执行：

echo 'export PATH="/usr/local/opt/openssl/bin:$PATH"' >> ~/.bash_profile

在~/.bash_profile中添加下面两条内容

export LDFLAGS="-L/usr/local/opt/openssl/lib"
export CPPFLAGS="-I/usr/local/opt/openssl/include"

执行完上述操作后，我的bash_profile文件如下截图：

3.第三步就是使你的bash_profile生效,再次尝试安装

source ~/.bash_profile