Flask render_template invalid syntax error with HTML

So I'm new to python and even newer to flask. I'm trying towrite the code for a website that will be run on a raspberry pi 4. It will hopefully turn on my PC via wake on LAN when I'm not at home with it.

Trying to run the code I wrote gives me an invalid syntax error. I tried fixing it, but with my limited knowledge I found that it's next to impossible.

The python code

# Import flask and wakeonlan modles
from flask import Flask
from flask import render_template
from wakeonlan import send_magic_packet

# Create flask app
app= Flask(__name__)

# Define the MAC adress of your PC.
PC_MAC = "Mac goes here,but I took it out before uploading to Stack Overflow. Don't worry, I did write this one correctly."

# Define a route for the home page
@app.route("/")
    # Render the index.html template
reder_template("index.html")

# Defines a route forthe wake up action
@app.route("/wakeup")
def wakeup():
    # Send a wake on lan packet to the PC
    send_magic_packet(PC_MAC)
    # Return a success messagesss
    return "Your PC has been turned on!"

# Run the app
if __name__ == "__main__":
    app.return()

The HTML code

<!DOCTYPE html>
<html>
    <head>
        <title>
            Wake on LAN website!
        </title>
    </head>
    <body>
        <h1>
            Wake on LAN Website.
        </h1>
        <p1>
            This website allows me to turn on my PC remotely using wake on lan.
        </p1>
        <button
        onclick="window.location.href='/wakeup'">
    <Turn on PC>   
    </button>
    </body>
</html>

The python file is located on the desktop and is called "app.py". The html file is located in Desktop/templates and is called "index.html".

Please explain to me what I did wrong and how to fix it as if I was a 5 year old, as that is how low my level of understanding python and flask goes.

(And yes, for the website I do have a DNS)

Solution

The reason code is throwing an Invalid Syntax error is because the render_template method needs to be returned from a function, and not called directly. Moreover, to run the app, you have to use app.run() not app.return()

The following modified code will work

# Import flask and wakeonlan modles
from flask import Flask
from flask import render_template

# Create flask app
app = Flask(__name__)

# Define the MAC adress of your PC.
PC_MAC = "Mac goes here,but I took it out before uploading to Stack Overflow. Don't worry, I did write this one correctly."

# Define a route for the home page
@app.route("/")
    # Render the index.html template
def homepage():
    return render_template("index.html")

# Defines a route forthe wake up action
@app.route("/wakeup")
def wakeup():
    # Send a wake on lan packet to the PC
    # Return a success messagesss
    return "Your PC has been turned on!"

# Run the app
if __name__ == "__main__":
    app.run()