Design a flask app that checks whether entered <name> in the URL is known or unknown code example

Example 1: python render_template

from flask import Flask
from flask import render_template
app = Flask(__name__)

@app.route('/')
def index():
   return render_template("index.html") #if you want to render a .html file,
                        # import render_template from flask and use
                        #render_template("index.html") here.

if __name__ == '__main__':
    app.debug = True
    app.run() #go to http://127.0.0.1:5000/ to view the page.

Example 2: default flask app

from flask import Flask
app = Flask(__name__)

@app.route('/')
def index():
    return 'Flask'