How to authenticate to yagmail on an SMTP server without authentication

yagmail_no_auth.py

# Couldn't find a reference on how to authenticate to an SMTP server that doesn't require authentication, but this worked.
# Based on the yagmail PyPi page: https://pypi.org/project/yagmail/ 
#   and yagmail docs: https://yagmail.readthedocs.io/en/latest/api.html#smtp-client

import yagmail

user_email = "my_email@somedomain.com"

yag = yagmail.SMTP(user=user_email, host='smtp.somedomain.com', port=25, smtp_skip_login=True, smtp_ssl=False)

contents = [
    "This is the body, and here is just text http://somedomain/image.png",
    "You can find an audio file attached.", '/local/path/to/song.mp3'
]
yag.send('some_email@anotherdomain.com', 'Testing', contents)