'Commit the `node` into the scheme.'

def commit_scheme_node(self, node):

    if (not self.editable):
        raise Exception('Scheme    not    editable.')
    if (node not in self.__item_for_node):
        raise ValueError("No    'NodeItem'    for    node.")
    item = self.__item_for_node[node]
    try:
        self.scheme.add_node(node)
    except Exception:
        log.error("An    error    occurred    while    committing    node    '%s'", node, exc_info=True)
        self.remove_node_item(item)
        raise
    log.info(("Commited    node    '%s'    from    '%s'    to    '%s'" % (node, self, self.scheme)))
