def validate_email_with_regex(email_address):
    """
    Note that this will only filter out syntax mistakes in emailaddresses.
    If a human would think it is probably a valid email, it will most likely pass.
    However, it could still very well be that the actual emailaddress has simply
    not be claimed by anyone (so then this function fails to devalidate).
    """
    if not re.match(VALID_ADDRESS_REGEXP, email_address):
        emsg = 'Emailaddress "{}" is not valid according to RFC 2822 standards'.format(
            email_address)
        raise YagInvalidEmailAddress(emsg)
    # apart from the standard, I personally do not trust email addresses without dot.
    if "." not in email_address and "localhost" not in email_address.lower():
        raise YagInvalidEmailAddress("Missing dot in emailaddress")