python flask 学习遇到的问题

学习中遇到以下报错
Environment: production
WARNING: This is a development server. Do not use it in a production deployment.
Use a production WSGI server instead.

Traceback (most recent call last):
File "/111/555.py", line 11, in
app.run()
File "/111/venv/lib/python3.6/site-packages/flask/app.py", line 920, in run
run_simple(t.cast(str, host), port, self, **options)
File "/111/venv/lib/python3.6/site-packages/werkzeug/serving.py", line 1017, in run_simple
inner()
File "/111/venv/lib/python3.6/site-packages/werkzeug/serving.py", line 966, in inner
fd=fd,
File "/111/venv/lib/python3.6/site-packages/werkzeug/serving.py", line 790, in make_server
host, port, app, request_handler, passthrough_errors, ssl_context, fd=fd
File "/111/venv/lib/python3.6/site-packages/werkzeug/serving.py", line 693, in init
super().init(server_address, handler) # type: ignore
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/socketserver.py", line 453, in init
self.server_bind()
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/server.py", line 136, in server_bind
socketserver.TCPServer.server_bind(self)
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/socketserver.py", line 467, in server_bind
self.socket.bind(self.server_address)
OSError: [Errno 48] Address already in use

应该是端口占用了
解决办法：
查看端口情况
sudo lsof -i tcp:port 如： sudo lsof -i tcp:5000
结束进程
sudo kill -9 PID
在run以下可以访问了