Close a node

        :param node_id: Node identifier

        :returns: Node instance

def close_node(self, node_id):
        """
        Close a node

        :param node_id: Node identifier

        :returns: Node instance
        """

        node = self.get_node(node_id)
        if asyncio.iscoroutinefunction(node.close):
            yield from node.close()
        else:
            node.close()
        return node