Random email.

    Usage Example::

        >>> rand_email()
        Z4Lljcbdw7m@npa.net

def rand_email():
    """Random email.

    Usage Example::

        >>> rand_email()
        Z4Lljcbdw7m@npa.net
    """
    name = rand_str(random.randint(4, 14), string.ascii_lowercase) + \
           rand_str(random.randint(1, 4), string.digits)
    domain = rand_str(random.randint(2, 10), string.ascii_lowercase)
    surfix = random.choice(DOMAIN_SURFIX)
    return "%s@%s.%s" % (name, domain, surfix)