Closes a VPCS VM.

        :returns: VPCSVM instance

def close_node(self, node_id, *args, **kwargs):
        """
        Closes a VPCS VM.

        :returns: VPCSVM instance
        """

        node = self.get_node(node_id)
        if node_id in self._used_mac_ids:
            i = self._used_mac_ids[node_id]
            self._free_mac_ids[node.project.id].insert(0, i)
            del self._used_mac_ids[node_id]
        yield from super().close_node(node_id, *args, **kwargs)
        return node