Python 2.4-compliant sendmail function

sendmail2.4.py

def sendmail(subject, to, sender, body, mailserver, body_type="html", attachments=None, cc=None):
    """Send an email message using the specified mail server using Python's
    standard `smtplib` library and some extras (e.g. attachments).

    NOTE: This function has no authentication.  It was written for a mail server
    that already does sender/recipient validation.

    WARNING: This is a non-streaming message system.  You should not send large
    files with this function!

    NOTE: The body should include newline characters such that no line is greater
    than 990 characters.  Otherwise the email server will insert newlines which
    may not be appropriate for your content.
    http://stackoverflow.com/a/18568276
    """
    msg = MIMEMultipart()
    msg['Subject'] = subject
    msg['From'] = sender
    msg['To'] = ', '.join(to)

    if cc:
        msg['Cc'] = ", ".join(cc)
    else:
        cc = []

    msg.attach(MIMEText(body, body_type))

    attachments = [] or attachments

    for attachment in attachments:
        part = MIMEBase('application', "octet-stream")
        part.set_payload(open(attachment, "rb").read())
        Encoders.encode_base64(part)

        part.add_header('Content-Disposition', 'attachment', filename=os.path.basename(attachment))

        msg.attach(part)

    server = smtplib.SMTP(mailserver)
    server.sendmail(sender, to + cc, msg.as_string())  # pragma: no cover