'Stop a running node.
:param node: The node to stop
:type node: :class:`Node`
:keyword ex_force_stop: if ``True``, stop node force (maybe lose data)
otherwise, stop node normally,
default to ``False``
:type ex_force_stop: ``bool``
:return: stopping operation result.
:rtype: ``bool``'

def ex_stop_node(self, node, ex_force_stop=False):

    params = {'Action': 'StopInstance', 'InstanceId': node.id, 'ForceStop': u(ex_force_stop).lower()}
    resp = self.connection.request(self.path, params)
    return (resp.success() and self._wait_until_state([node], NodeState.STOPPED))
