'Assigns a new IP address to the server
:param server_id: Id of the server
:rtype: ``str``
:param ip_type: Type of the IP address [IPV4,IPV6]
:rtype: ``str``
:return: ``Node`` instance
:rtype: ``Node``'

def ex_assign_server_ip(self, server_id, ip_type):

    body = {'type': ip_type}
    response = self.connection.request(action=('servers/%s/ips' % server_id), data=body, method='POST')
    return self._to_node(response.object)
