pip install robotframework-sshlibrary提示： Microsoft Visual C++ 9.0 is required

win7下 pip install robotframework-sshlibrar时提示：

error: Microsoft Visual C++ 9.0 is required (Unable to find vcvarsall.bat).
Get it from http://aka.ms/vcpython27

解决办法：安装Micorsoft Visual C++ Compiler for Python 2.7

下载地址：http://www.microsoft.com/en-us/download/details.aspx?id=44266