how to change port in flask app

1from flask import Flask
2app = Flask(__name__)
3
4@app.route("/")
5def hello():
6    return "Hello World!"
7
8if __name__ == '__main__':
9    app.run(host="localhost", port=8000, debug=True)

1if __name__ == "__main__":
2    app.run(host='127.0.0.1', port=5002)

1flask run -h localhost -p 3000