Fatal error in launcher: Unable to create process
本地同时安装了python2.7.9和python3.5.2，python2要安装selenium，执行命令：pip2 install selenium 时报错：
Fatal error in launcher: Unable to create process using '"D:\Python27\python.exe
" "D:\Python27\Scripts\pip2.exe" install selenium'
解决方法;打开对应的目录，D:\Python27\Scripts，输入命令 python2 -m pip install -upgrade pip后重新执行pip2 install selenium 即可，