Vet a given E-mail address

vet_email.py

def vet_email(email_address):
    """Vet email addresses. The local part (the part before the '@') must not
    exceed 64 characters and the domain part (after the '@') must not
    exceed 255 characters. The entire email address length must not exceed
    320 characters.
    """
    local_part  = re.sub(r'^([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})$', '\\1', email_address)
    domain_part = re.sub(r'^([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})$', '\\2', email_address)
    if len(local_part) > 64:
        return False
    if len(domain_part) > 255:
        return False
    return True