Send markdown email

    Args:
        email (str/obj): A markdown string or EmailContent object 
        subject (str): subject line
        from_email (str): sender email address
        to_email (str/list): recipient email addresses
        cc (str/list): CC email addresses (string or a list)
        bcc (str/list): BCC email addresses (string or a list)
        reply_to (str): Reply-to email address
        smtp (dict): SMTP configuration (dict)

    Schema of smtp dict:
        host (str): SMTP server host. Default: localhost
        port (int): SMTP server port. Default: 25
        tls (bool): Use TLS. Default: False
        ssl (bool): Use SSL. Default: False
        user (bool): SMTP login user. Default empty
        password (bool): SMTP login password. Default empty

def send(email, subject=None,
         from_email=None, to_email=None,
         cc=None, bcc=None, reply_to=None,
         smtp=None):
    """Send markdown email

    Args:
        email (str/obj): A markdown string or EmailContent object 
        subject (str): subject line
        from_email (str): sender email address
        to_email (str/list): recipient email addresses
        cc (str/list): CC email addresses (string or a list)
        bcc (str/list): BCC email addresses (string or a list)
        reply_to (str): Reply-to email address
        smtp (dict): SMTP configuration (dict)

    Schema of smtp dict:
        host (str): SMTP server host. Default: localhost
        port (int): SMTP server port. Default: 25
        tls (bool): Use TLS. Default: False
        ssl (bool): Use SSL. Default: False
        user (bool): SMTP login user. Default empty
        password (bool): SMTP login password. Default empty
    """
    if is_string(email):
        email = EmailContent(email)

    from_email = sanitize_email_address(from_email or email.headers.get('from'))
    to_email = sanitize_email_address(to_email or email.headers.get('to'))
    cc = sanitize_email_address(cc or email.headers.get('cc'))
    bcc = sanitize_email_address(bcc or email.headers.get('bcc'))
    reply_to = sanitize_email_address(reply_to or email.headers.get('reply-to'))

    message_args = {
        'html': email.html,
        'text': email.text,
        'subject': (subject or email.headers.get('subject', '')),
        'mail_from': from_email,
        'mail_to': to_email
    }
    if cc:
        message_args['cc'] = cc
    if bcc:
        message_args['bcc'] = bcc
    if reply_to:
        message_args['headers'] = {'reply-to': reply_to}

    message = emails.Message(**message_args)

    for filename, data in email.inline_images:
        message.attach(filename=filename, content_disposition='inline', data=data)

    message.send(smtp=smtp)