我尝试在 macOS Catalina 上将 python2.7 升级到 python3，当我运行时brew doctor，它显示：
Warning: Homebrew's sbin was not found in your PATH but you have installed
formulae that put executables in /usr/local/sbin.
Consider setting the PATH for example like so:
echo 'export PATH="/usr/local/sbin:$PATH"' >> ~/.zshrc
所以我尝试了echo 'export PATH="/usr/local/sbin:$PATH"' >> ~/.zshrc不起作用的命令。