'Updates a Public IP
:param ip_id: ID of public IP
:rtype: ``str``
:param reverse_dns: Reverse DNS
:rtype: ``str``
:return: Instance of Public IP
:rtype: ``dict``'

def ex_update_public_ip(self, ip_id, reverse_dns):

    body = {'reverse_dns': reverse_dns}
    response = self.connection.request(action=('public_ips/%s' % ip_id), data=body, method='DELETE')
    return response.object
