In bottle you can generate a custom HTTP response code by first importing HTTPResponse:
from bottle import HTTPResponse
and then, in your @route function, raise a HTTPResponse, for example
raise HTTPResponse("This is a HTTP 401 test URL", status=401)
Full example
#!/usr/bin/env python3
from bottle import HTTPResponse, route, run
@route('/test401')
def hello():
raise HTTPResponse("This is a HTTP 401 test URL", status=401)
run(host='localhost', port=8080, debug=True)
Run this, script, then open http://localhost/test401 which will result in a HTTP 401 (unauthorized) response code with
This is a HTTP 401 test URL
as response body.