How to send emails programmatically and hide the sender address?

I would like to send mail notifications to my customers via python. The problem is the sender mail account needs to be hidden. Just to be clear - this is not for phishing or spamming, only personal use!

I used smtplib and setup a new 'noreply' account in gmail, but even when providing an alias to the message, the 'mail from:' header contains my actual mail.

import smtplib
from email.mime.text import MIMEText
from email.utils import *

email_sender = 'noreply%%@gmail.com'
email_receiver = 'example%%%@gmail.com'

subject = 'Python!'

msg = MIMEText('This is the body of the message.')
msg['To'] = formataddr(('Recipient', 'example%%%@gmail.com'))
msg['From'] = formataddr(('Author', 'author@example.com'))
msg['Subject'] = 'Simple test message'

connection = smtplib.SMTP('smtp.gmail.com', 587)
connection.starttls()
connection.login(email_sender, 'password')
connection.sendmail(msg['From'], email_receiver, msg.as_string())
connection.quit()

I get the mail in to my inbox as expected but when clicking 'more details' the original sender address appears.