'Produce an Internet domain name with the specified number of
subdomain levels.
>>> domain_name()
nichols-phillips.com
>>> domain_name(2)
williamson-hopkins.jackson.com'

def domain_name(self, levels=1):

    if (levels < 1):
        raise ValueError(u'levels    must    be    greater    than    or    equal    to    1')
    if (levels == 1):
        return ((self.domain_word() + u'.') + self.tld())
    else:
        return ((self.domain_word() + u'.') + self.domain_name((levels - 1)))
