Python Mac安装bs4:Could not install packages due to an EnvironmentError: [Errno 13] Permission denied

安装命令：
pip3 install bs4

日志：
Could not install packages due to an EnvironmentError: [Errno 13] Permission denied: '/Library/Python/3.7' Consider using the '--user' option or check the permissions.

  Using cached https://files.pythonhosted.org/packages/10/ed/7e8b97591f6f456174139ec089c769f89a94a1a4025fe967691de971f314/bs4-0.0.1.tar.gz
Collecting beautifulsoup4 (from bs4)
  Using cached https://files.pythonhosted.org/packages/cb/a1/c698cf319e9cfed6b17376281bd0efc6bfc8465698f54170ef60a485ab5d/beautifulsoup4-4.8.2-py3-none-any.whl
Collecting soupsieve>=1.2 (from beautifulsoup4->bs4)
  Downloading https://files.pythonhosted.org/packages/05/cf/ea245e52f55823f19992447b008bcbb7f78efc5960d77f6c34b5b45b36dd/soupsieve-2.0-py2.py3-none-any.whl
Building wheels for collected packages: bs4
  Building wheel for bs4 (setup.py) ... done
  Stored in directory: /Users/apple/Library/Caches/pip/wheels/a0/b0/b2/4f80b9456b87abedbc0bf2d52235414c3467d8889be38dd472
Successfully built bs4
Installing collected packages: soupsieve, beautifulsoup4, bs4
Could not install packages due to an EnvironmentError: [Errno 13] Permission denied: '/Library/Python/3.7'
Consider using the `--user` option or check the permissions.

再次安装：
pip3 install bs4 --user

日志：

Collecting bs4
Collecting beautifulsoup4 (from bs4)
  Using cached https://files.pythonhosted.org/packages/cb/a1/c698cf319e9cfed6b17376281bd0efc6bfc8465698f54170ef60a485ab5d/beautifulsoup4-4.8.2-py3-none-any.whl
Collecting soupsieve>=1.2 (from beautifulsoup4->bs4)
  Using cached https://files.pythonhosted.org/packages/05/cf/ea245e52f55823f19992447b008bcbb7f78efc5960d77f6c34b5b45b36dd/soupsieve-2.0-py2.py3-none-any.whl
Installing collected packages: soupsieve, beautifulsoup4, bs4
Successfully installed beautifulsoup4-4.8.2 bs4-0.0.1 soupsieve-2.0

---