'Gets a server
:param server_id: Id of the server to be retrieved
:rtype: ``str``
:return:    Instance of class ``Node``
:rtype:     :class: `Node`'

def ex_get_server(self, server_id):

    response = self.connection.request(action=('servers/%s' % server_id), method='GET')
    return self._to_node(response.object)
