[Python] smtplib (with BCC)

def send(to, cc, bcc, subject, text, html):
    message = MIMEMultipart("alternative")
    message["Subject"] = subject
    message["From"] = MAIL_FROM
    message["To"] = to
    message["Cc"] = cc + "," + MAIL_DL

    if html is not None:
        body = MIMEText(html, "html")
    else:
        body = MIMEText(text)
    message.attach(body)

    server = smtplib.SMTP(MAIL_SERVER)
    server.set_debuglevel(1)

    server.sendmail(MAIL_DL, to.split(",") + bcc.split(","), message.as_string())
    server.quit()

    return {
        "to": to,
        "cc": cc,
        "bcc": bcc,
        "subject": subject,
        "text": text,
        "html": html,
    }

https://stackoverflow.com/questions/43017496/bcc-not-hidden-on-gmail-using-python-smtplib/68511164#68511164

BCC not hidden on gmail using python smtplib