Sending gmail with no clear password

[zljubisicmob at gmail.com]

Hi,

I have a python3 script that runs 24/7 on linux (raspberry pi) server. 
It would be very nice for the script to be able to send an email message about certain statuses.

As the linux server is headless, I don't have an option to key in the password while starting the script.
Furthermore, from time to time I restart the server remotely, so password should be somewhere in the system but kept more secure than hardcoded in the python script.

I understand that I can send email by using let's say procedure from the https://rajivpandit.wordpress.com/2013/09/19/how-to-send-email-by-python/

On the link above there are two approaches. One with no need for any authentication or password, but that approach doesn't work.
It is written for python 2 but that is what I need.

What are my options?

Regards.