我想建立mbed库，所以我运行 /mbed-master/workspace_tools/build.py 但我得到了这个错误：
MacBook-Pro-de-joanet:workspace_tools joanet$ ./build.py
env: python2: No such file or directory
但我在PATH中有它：
MacBook-Pro-de-joanet:workspace_tools joanet$ echo $PATH
/usr/bin/python2.7:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/opt/X11/bin
MacBook-Pro-de-joanet:workspace_tools joanet$