Send Mail using docker as a relay

sendmail.py

#!/usr/bin/env python3

# Start a mail relay using docker:
#
#    docker run -p 25:25 namshi/smtp
#

import smtplib
from email.message import EmailMessage
from email.headerregistry import Address
from email.utils import make_msgid
import csv


def mail_send(to_address, first, last):
    if (not first or len(first) < 2):
        first = 'Customer'

    print("EmailAddress: {}, FirstName: {}, LastName: {}".format(to_address, first, last))

    message = EmailMessage()
    message['Subject'] = "Subject"
    message['From'] = Address("Customer Enquiries", "customer.enquiries", "example.com")
    message['To'] = to_address
    message.add_header('Content-Type', 'text/html', charset='utf-8')

    tvx_cid = make_msgid()

    with open("body.html") as html_body_raw:
        html_body = html_body_raw.read()
        html_body = html_body.replace('__cid_tvx__', tvx_cid[1:-1]).replace('__first__', first)
        print("html_body: {}".format(html_body))
        message.set_content(html_body, subtype='html')

    with open("tvx.png", 'rb') as img:
        message.add_related(img.read(), 'image', 'png', cid=tvx_cid)

    with open('{}_{}.msg'.format(first, last), 'wb') as f:
        f.write(bytes(message))

    with smtplib.SMTP('localhost') as s:
        s.send_message(message)


csv_reader = csv.reader(open('list.csv', 'r'))

for record in csv_reader:
    mail_send(record[2], record[0], record[1])