No-external-dependency email sending function through Mailgun's REST api for python

mailgun.py

# -*- coding: utf-8 -*-

"""
Copyright 2016 Sean Beck, Matteo Scotuzzi
MIT license

A simple script that provides a function to send an email via Mailgun with no 
external dependencies.
This requires obtaining an API key from Mailgun. Make also sure to setup the defaults in the 
MAILGUN_API_KEY, DEFAULT_EMAIL_SENDING_DOMAIN, DEFAULT_EMAIL_SENDING_ADDRESS constants after 
the imports.
Mailgun will generate a sending domain for you, so just use that if you do not have your own domain.
"""
try:
    # For Python 3.0 and later
    from urllib.request import urlopen, Request
except ImportError:
    # Fall back to Python 2's urllib2
    from urllib2 import urlopen, Request
import urllib
import base64

MAILGUN_API_KEY = 'key-xxx'
DEFAULT_EMAIL_SENDING_DOMAIN = 'example.com'
DEFAULT_EMAIL_SENDING_ADDRESS = '[email protected]'


def mailgun_notify(**kwargs):
    """
    :param kwargs: Pass in a dictionary like so containing your args - mailgun_notify(**d)
    :return: None

    param api_key: Your Mailgun API key
    param domain: The domain associated with your Mailgun account
    param from: A string representing the sending email address. This usually
                 looks something like "Mailgun <[email protected]>"
    param to: A list of strings representing email addresses of your intended
                 recipients (cc and bcc require the same kind of data in input)
    param subject: A string to be used as your email's subject
    param text: A string representing the body of your email in text.

    Those are basic parameters to the Mailgun API. This function requires you specify "to" and
    "subject" parameters while others are optional (as long as you set the default constants above:
    MAILGUN_API_KEY, DEFAULT_EMAIL_SENDING_DOMAIN, DEFAULT_EMAIL_SENDING_ADDRESS).
    All other possible parameters that can be sent via the API can be found here:
    https://documentation.mailgun.com/api-sending.html#sending.
    If you want an HTML email instead of a text-based email, use the "html" parameter instead of "text"
    """
    params = ['to', 'subject']
    if any(param not in kwargs for param in params):
        raise Exception('Please specify all params: {}'.format(params))
    kwargs['api_key'] = kwargs.pop('api_key', MAILGUN_API_KEY)
    kwargs['domain'] = kwargs.pop('domain', DEFAULT_EMAIL_SENDING_DOMAIN)
    kwargs['from'] = kwargs.pop('from', DEFAULT_EMAIL_SENDING_ADDRESS)
    kwargs['to'] = ','.join(kwargs['to'])
    if 'bcc' in kwargs:
        kwargs['bcc'] = ','.join(kwargs['bcc'])
    if 'cc' in kwargs:
        kwargs['cc'] = ','.join(kwargs['cc'])
    data = {param: kwargs[param] for param in kwargs if param not in ['api_key', 'domain']}

    url = 'https://api.mailgun.net/v3/{}/messages'.format(kwargs['domain'])
    data = urllib.urlencode(data)

    req = Request(url, data)
    base64string = base64.encodestring('%s:%s' % ('api', kwargs['api_key'])).replace(
        '\n', '')
    req.add_header("Authorization", "Basic %s" % base64string)
    response = urlopen(req)
    if response.getcode() != 200:
        raise Exception('Request was not successful. Status code: {}'.format(req.status_code))