Linux subdomain creation problem

Generalize

One day, when I was using my linux to debug a web page, I suddenly encountered such an error
code:

import flask
app = flask.Flask(__name__)
@app.route('/',subdomain='123')
def home_123():
    return 'hello world'
app.config['SERVER_NAME'] = 'test.com:5000'
app.run()

Error:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/***马赛克***/anaconda3/lib/python3.7/site-packages/flask/app.py", line 943, in run
    run_simple(host, port, self, **options)
  File "/Users/***马赛克***/anaconda3/lib/python3.7/site-packages/werkzeug/serving.py", line 814, in run_simple
    inner()
  File "/Users/***马赛克***/anaconda3/lib/python3.7/site-packages/werkzeug/serving.py", line 774, in inner
    fd=fd)
  File "/Users/***马赛克***/anaconda3/lib/python3.7/site-packages/werkzeug/serving.py", line 660, in make_server
    passthrough_errors, ssl_context, fd=fd)
  File "/Users/***马赛克***/anaconda3/lib/python3.7/site-packages/werkzeug/serving.py", line 577, in __init__
    self.address_family), handler)
  File "/Users/***马赛克***/anaconda3/lib/python3.7/socketserver.py", line 452, in __init__
    self.server_bind()
  File "/Users/***马赛克***/anaconda3/lib/python3.7/http/server.py", line 137, in server_bind
    socketserver.TCPServer.server_bind(self)
  File "/Users/***马赛克***/anaconda3/lib/python3.7/socketserver.py", line 466, in server_bind
    self.socket.bind(self.server_address)
OSError: [Errno 49] Can't assign requested address

I immediately understood that my SERVER_NAME is "test.com:5000", but I did not match the domain name "test.com:5000" to the local.
Oh, yes, I have to match the domain name of 123.test.com:5000.
The following is the process

process

First, to configure the domain name, you need to modify "/etc/hosts" to
execute the command:

sudo vim /etc/hosts

After the following scene appears, enter the password (may not appear) After the

input is completed, the following scene appears:

add as required, format:

127.0.0.1       <将此处替换成你需要的>

For example, what I need to add:

127.0.0.1       test.com
127.0.0.1       123.test.com

Result: At

this point, it is complete

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Author

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